COWEN HEALTH CARE CONFERENCE Dr. Elias Zerhouni

President, Global Research & Development

March 6, 2012

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Forward Looking Statements

This presentation contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995, as amended. Forward-looking statements are statements that are not historical facts. These statements include projections and estimates and their underlying assumptions, statements regarding plans, objectives, intentions and expectations with respect to future financial results, events, operations, services, product development and potential, and statements regarding future performance. Forward-looking statements are generally identified by the words “expects”, “anticipates”, “believes”, “intends”, “estimates”, “plans” and similar expressions. Although Sanofi’s management believes that the expectations reflected in such forward-looking statements are reasonable, investors are cautioned that forward-looking information and statements are subject to various risks and uncertainties, many of which are difficult to predict and generally beyond the control of Sanofi, that could cause actual results and developments to differ materially from those expressed in, or implied or projected by, the forward-looking information and statements. These risks and uncertainties include among other things, the uncertainties inherent in research and development, future clinical data and analysis, including post marketing, decisions by regulatory authorities, such as the FDA or the EMA, regarding whether and when to approve any drug, device or biological application that may be filed for any such product candidates as well as their decisions regarding labelling and other matters that could affect the availability or commercial potential of such product candidates, the absence of guarantee that the product candidates if approved will be commercially successful, the future approval and commercial success of therapeutic alternatives, the Group’s ability to benefit from external growth opportunities, trends in exchange rates and prevailing interest rates, the impact of cost containment policies and subsequent changes thereto, the average number of shares outstanding as well as those discussed or identified in the public filings with the SEC and the AMF made by Sanofi, including those listed under “Risk Factors” and “Cautionary Statement Regarding Forward-Looking Statements” in Sanofi’s annual report on Form 20-F for the year ended December 31, 2010. Other than as required by applicable law, Sanofi does not undertake any obligation to update or revise any forward-looking information or statements.

Sanofi Grew Sales in 2011 due to Genzyme Acquisition and Growth Platforms

2011

€33,389m

2010

€32,367m

2009

€29,306m

2008

€27,568m

Sales

+5.3% at CER

3 (1) In 2008 and 2009, Merial Joint Venture sales w ere not consolidated by Sanofi (2) In 2010, excluding non-consolidated sales from Merial, Sanofi reported sales of €30,384m

(1) (1) (2)

2009 2011 2010 2008

% of Total

42.7% 65.0%

Sales of Growth Platforms(1) & Genzyme

Sanofi Boosted Sales of its Growth Platforms and Significantly Reduced its Patent Cliff Exposure in 2011

(1) 2010 include sales of Merial. In 2008 and 2009, Merial Joint Venture sales w ere not consolidated by Sanofi (2) Lovenox® U.S., Plavix® Western EU, Taxotere® Western EU & U.S., Eloxatin® U.S., Ambien CR® U.S., Allegra® U.S., Aprovel® Western EU, Xyzal® U.S., Xatral® U.S., Nasacort® U.S. - Generic makers of oxaliplatin required to cease selling in the U.S. since June 30, 2010 but judgement is under appeal by Sun.

2011 2009 2010 2008

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% of Total

27.4% 9.4%

Sales of Key Genericized Products(2)

€21,703m

€11,783m

€3,152m

€7,565m

€6.61

2011

€6.65

2010

€7.06

2009 2008

€5.59

Patent Cliff Impact on EPS Mitigated in 2011

Business EPS

5

-3.8% at CER

Executing Successful Strategy to Reposition Sanofi

Deliver sustainable growth

and generate improved

shareholder returns Adapt structure for future challenges and opportunities 3

Pursue external growth opportunities 2

Increase innovation in R&D 1

6 6

Executing our R&D Strategy

Global R&D

Goals

An efficient global R&D organization Maximize synergies and convergence around Hub model Exploit economies of scale Improve R&D cost structure

Focus on high-value projects

Execute on late-stage projects Medical value and translational feasibility to guide early-stage

portfolio prioritization

Establish new models of external innovation Enhance the value of external opportunities and partnerships Create open and creative model of pharma-biotech partnership

e.g. Warp Drive Bio

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Focusing on Delivering a Promising Development Portfolio

Achieve Regulatory Milestones

• Lemtrada™

• Aubagio™

• Lyxumia® (1)

• Zaltrap® (2) • Visamerin®

• Kynamro™ (3)

Next Wave of Late-Stage Projects

• New glargine formulation • Glargine-lixisenatide combo • Dengue vaccine • Eliglustat • Anti-PCSK-9 mAb

EU/U.S. EU

EU/U.S. EU/U.S.

EU

• Otamixaban • Sarilumab • JAK-2 inhibitor • Iniparib • Ombrabulin

Short-term opportunities

Mid-term opportunities

Submitted

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Lemtrada™, Aubagio™, Lyxumia®, Zaltrap®, Visamerin® and Kynamro™ are registered trade names submitted to health authorities for investigational agents (1) In-licensed from Zealand Pharma A/S (2) Partnership w ith Regeneron (3) In-licensed from Isis Pharmaceuticals

Efficacy with manageable safety

Convenience & efficacy

Early MS/CIS(1) RRMS(2) and early active MS

RMS(3) severe/ highly active

Emergence of a Franchise Addressing the Full Spectrum of Patient Needs in Multiple Sclerosis

Lemtrada™

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Aubagio®

Convenience & safety

Rebif®

Lemtrada™

Aubagio™

CIS – Clinically Isolated Syndrome, TOPIC Phase III study presently ongoing RRMS – Relapse Remitting Multiple Sclerosis RMS – Relapsing Multiple Sclerosis

Genzyme - MS

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A Unique Value Proposition: Superior Efficacy with Convenient Annual Dosing

CARE-MS I CARE-MS II

Patients 581 840

Study Duration 2 years 2 years

Patient Population

Treatment naïve

Relapsed on prior treatment

Treatment Arms

Alemtuzumab vs. IFNβ 1a

Alemtuzumab vs. IFNβ 1a

Relapse Rate Reduction at 2 Years(1)

55% (p<0.0001)

49% (p<0.0001)

Sustained Accumulation of Disability Reduction in

6 Months(1) (ns) 42%

(p=0.0084)

● Superior efficacy in Phase III vs. Rebif®

● Manageable safety:

● Well-characterized and consistent across studies

● Effective risk management when events identified early

ANN – American Academy of Neurology (1) Co-primary endpoints in CARE-MS I and CARE-MS II 10

Genzyme - MS

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Aubagi A Once-Daily Oral Therapy with Comparable Efficacy to Injectable Interferon

● Efficacy demonstrated in TEMSO on both Relapse Rate and Disability Progression at 14mg

● No superiority vs. Rebif® in TENERE but lower rate of TEAE-related discontinuation

● Manageable safety profile with up to 10 years of follow-up

(1) Adjusted for Expanded Disability Status Scale score strata at baseline and takes duration of treatment into account. TEAE – Treatment Emergent Adverse Events, ACTRIMS - Americas Committee for Treatment and Research in Multiple Sclerosis ENS – European Neurological Society, ARR – Annualized Relapse Rate, RRR – Relative risk reduction, HRR – Hazard ratio reduction

TEMSO: Reduction in Adjusted(1) ARR

RRR: 31.2% p=0.0002

RRR: 31.5% p=0.0005

0%

20%

10%

HRR: 23.7% p=ns

HRR: 29.8% p=0.0279

30% Placebo T. 7 mg T. 14 mg

Week

TEMSO: Reduction in Disability Progression (%)

Genzyme - MS

0 0,1 0,2 0,3 0,4 0,5 0,6

T. 14 mg

T. 7 mg

Placebo

0 12 24 36 48 60 72 84 96 108

A GLP-1 Agonist with Unique Post-Prandial Effect and One Step Titration

Mono Mono Japan

Drug naïve patients

Placebo-controlled in OAD failure

M (metformin)

F1 (metformin)

M Asia (metformin)

S (sulfonylurea)

P (pioglitazone)

X vs. exenatide Active-controlled

L

L Asia Placebo-controlled on

top of basal insulin

Placebo-controlled Secondary prevention

Cardiovascular Outcomes Study

Reported

Lixisenatide w as in-licensed from Zealand Pharma A/S. Lyxumia® is the intended trademark for lixisenatide. Lixisenatide is currently not approved or licensed anyw here in the w orld. 12

Duo 1 (Lantus®)

Consistent GLP-1 class effects of A1c reduction and weight loss

Pronounced effect on post-prandial glucose

Favorable safety profile with low risk of hypoglycemic events

OD injection, simple 1 step to maintenance dose, 1 pen per dose

Lyxumia® Profile

® Diabetes

Ongoing

● 3 positive GetGoal trials with Lyxumia® on top of basal insulin

● A1c target and PPG control achieved when used on top of Lantus® in GetGoal-Duo 1(3)

● Development of injection device for variable Lantus® dose with fixed Lyxumia® dose on track for Phase III initiation early 2013

T2D Patients Treated with Basal Insulin(1)

(worldwide)

On basal insulin On basal insulin with controlled fasting

glucose control but A1c >7%

4 million

T2D – Type 2 Diabetes, A1C – Glycated hemoglobin, PPG – Post Prandial Glucose (1) Adapted from IMS data (2) Includes all types of basal insulins (3) Top line results press release (6 Dec 2011) – Full results expected at a forthcoming scientif ic meeting

Optimal Complementary Pharmacological Profile with Basal Insulins

Diabetes ®

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4 million on other

basal insulins(2)

4 million on Lantus®

New Glargine Formulation with Unique Pharmacokinetics

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New Insulin Glargine Formulation Depot formation after subcutaneous injection

PK/PD: Pharmacokinetic/pharmacodynamic T2D: Type 2 Diabetes

Schematic illustration

● New glargine formulation provides

● Unique flat PK/PD profile

● Lower injection volume

● Phase III trials recently initiated in T2D high dose insulin users

● Targeting ~1,600 patients

Diabetes

Lantus® New Glargine Formulation

Strenghtening our Portfolio of Oncology Drugs

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● A novel VEGF trap acting on multiple angiogenic targets

● Previously treated metastatic colorectal cancer

● VELOUR: Significant improvement in Overall Survival

● Manageable safety profile consistent with previous studies

Zaltrap® aflibercept

NSCLC – Non Small Cell Lung Cancer VTE – Venous Thrombo Embolism (includes Deep Venous Thrombosis and Pulmonary Embolism)

Oncology

● Only ultra-LMWH effective in reducing VTE risk reduction in chemo-treated cancer patients

● Without impact on major bleeding incidence

● Treatment effect consistent across solid tumor types, stages and geographical regions

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Kynamro™: Targeting Rare Familial Hypercholesterolemias

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(1) Patients for hoFH and Severe FH in US and EU markets hoFH – Homozygous Familial Hypercholesterolemia Severe FH – Severe Familial Hypercholesterolemia = treated LDL-C CHD – Coronary Heart Disease heFH – Heterozygous familial hypercholesterolemia

● Four Phase III trials conducted in severe forms of hypercholesterolemia ● Sustained reduction in apo B production

resulting in significant decreases in LDL-C and Lp(a) when added to a regimen of maximally tolerated statin dose and other lipid lowering therapies

● Adverse reactions include ISRs, FLS, and elevations in liver transaminases and fat ● Liver fat stabilized or decreased in some

patients with treatment beyond 12 months

HeFH: 1 million patients

HoFH Severe FH

Understanding Rarity

~40,000 patients(1)

On statins: 60 million patients

ISR – Injection Site Reactions FLS – Flu Like Symptoms

PCSK9 mAb: a First in Class Addressing Unmet Needs in Hypercholesterolemias

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LDL-C Dose Response (Phase Ib) Atorvastatin Combo-Rx, heFH & Non-FH Combined

-70

-60

-50

-40

-30

-20

-10

0

10

1 15 29 43 57 71 85Study Day

Série1 Série2 Série3 Série4

Mean Percent Change from Baseline in Calculated LDL-C (%)

= Dose administered

Placebo 50 mg 100 mg 150 mg

CHD – Coronary Heart Disease, heFH – Heterozygous familial hypercholesterolemia , ACC – American College of Cardiology (1) Cohen JC. N Engl J Med 2006;354(12):1264-72

● Landmark study demonstrated that when PCSK9 is disabled, cholesterol and risk of CHD are greatly lowered(1)

● Preliminary Phase II data ● >65% LDL-C reduction in FH and

primary hypercholesterolemia on top of baseline statin use

● Generally safe and well tolerated ● Phase II data to be presented at

the upcoming ACC medical meeting

● Phase III targeted to start Q2 2012

G. Sw ergold et al. Circulation 2011; 124: A16265

Metabolic Disorders

Otamixaban: Providing Superior Outcomes while Simplifying Treatment during Interventional Procedures

● Despite current therapies, death, MI, and readmission rates remain high

● Otamixaban is the first IV direct and selective factor Xa inhibitor with quick onset/offset

● 27 to 42% risk reduction in ACS complications including death and MI in Phase Il(1)

● Phase III TAO study ongoing and expected to complete by end 2012

(1) The Lancet, Volume 374, Issue 9692, Pages 762 - 764, 5 September 2009 NSTE-ACS – Non-ST-Elevation Acute Coronary Syndrome, MI – Myocardial Infarction, UFH – Unfractionated Heparin

TAO Study

Moderate-to-high risk NSTE-ACS with planned early invasive strategy (n=13,220)

Primary endpoint: Death/Myocardial Infarction @ day 7

Otamixaban Regimen 2 (n=1,969)

Otamixaban Regimen 1 (n=1,969)

UFH + Eptifibatide (n=1,969)

R

Thrombosis

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Sponsor-blinded interim analysis

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Eliglustat: a Novel Oral Therapy in Gaucher Disease(1)

● Potent, novel substrate inhibitor

● Convenience of oral therapy ● Eliminating challenges of

infusing patients

● Clinical profile expected to be similar to Cerezyme®

● 4-year Phase II data at WORLD congress in February 2012

● Phase III trials fully recruited

(1) Investigational drug (2) Patient from Phase II clinical trial WORLD – World Organization of Research on Lysosomal Diseases

December 2006 pre-treatment (18 years)

December 2009 3 years post treatment (21 years)(2)

Genzyme - Rare Diseases

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Eliglustat Clinical Data Comparable to Cerezyme®

Platelets +95%

Hemoglobin +2.3 g/dL

-4

-2

0

2

4

Hb Change from Baseline

(g/dL)

-100%

-50%

0%

50%

100%

Mean % Change

from Baseline

Liver -28%

Spleen -63%

Year 1

Year 2 Year 3 Year 4 Baseline

(1) Cerezyme® Registry Data on File – Upper and Low er 95% Confidence Interval around Mean

Eliglustat Phase 2 Trial Results: Treatment Changes to 4 Years(1)

Cerezyme® Range

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Dengue Vaccine: Addressing a Growing Global Threat

Ambitious R&D Program

● Global Phase III program (43,000 individuals)

● 1st efficacy results expected by end of 2012

● First submissions planned in 2013

Significant Disease Burden

● Estimated 220m dengue infections worldwide per year

● 2m cases of Hemorrhagic Fever

● >500,000 hospitalizations and >20,000 deaths / year

● Dengue: a public health priority in Asia and Latin America

Vaccines

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Rare Diseases & MS

Diabetes Oncology Other Pharma

Ophthalmology

Vaccines

Eighteen Potential New Launches over 2012-2015

5 8

Kynamro™ (mipomersen)

14

18

Lemtrada™ (alemtuzumab)

Aubagio™ (teriflunomide)

Lyxumia® (lixisenatide)

Zaltrap® (aflibercept)

Visamerin® (semuloparin)

Hexaxim®

ombrabulin

Dengue vaccine

eliglustat

SAR302503 (JAK-2 inhibitor)

otamixaban

DTP-HepB-Polio-Hib

FOV1101 (prednisporin)

SAR236553 anti-PCSK-9 mAb

iniparib

2012 2013 2014 2015

Cumulative Number of Projects Pharmaceuticals (excluding LCM) and Vaccines

Fluzone® QIV IM

Quadracel®

Note: Scope includes pharmaceuticals NMEs (excluding LCM – Life cycle management) and vaccines. Only f irst launches in a given market are mentioned. 22

hoFH – Homozygous Familial Hypercholesterolemia m-CRC – Metastatic Colorectal Cancer RMS – Relapsing forms of Multiple Sclerosis

Multiple Important Catalysts in 2012

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Zaltrap®, Lemtrada™, Aubagio™ and Kynamro™ are registered trade names submitted to health authorities for investigational agents

2012 Expected Regulatory Submissions Q1 Q2 Q3 Q4 ● Kynamro™ (mipomersen) in hoFH in the U.S. ● Lemtrada™ (alemtuzumab) in RMS in the U.S. and EU ● Lyxumia® (lixisenatide) in Type 2 diabetes in the U.S. Expected Headline Data Releases ● Zaltrap® (aflibercept) - Phase III results in 1st line prostate cancer (VENICE) ● Aubagio™ (teriflunomide) - Phase III results in RMS (TOWER) ● Lantus® - Phase III results in reduction in CV morbidity & mortality (ORIGIN) ● Otamixaban - Phase III study completion in ACS Expected Phase III Study Initiations ● New insulin glargine formulation - Phase III in diabetes (EDITION)

● Anti-PCSK-9 mAb - Phase III trials in hypercholesterolemia

Continued Execution of Strategy Expected to Deliver Sustainable Growth 2012-2015

2012-2015 Sales CAGR

Diversified sources of growth

Scale in businesses with significant barriers to entry

Low small molecule patent exposure in mature markets(1)

Large Emerging Markets presence(2)

Potential new product launches(3)

Operating margin evolution

2012-2015 Business EPS CAGR

Increased dividend payout ratio(4)

(1) 2012 sales from chemical products exposed to patent expiry in the U.S., Japan and Western Europe over 2012/2015 (2) Based on 2015 internal estimates (3) Over 2012-2015 (4) Dividend paid in 2014

~6%

50% of 2013 results

18

38-40%

Rebounding

> Sales CAGR

At least 5%

24