GenSight Biologics S A : Corporate presentation, June 2020

Disclaimer

This document contains forward-looking statements and estimates made by the GenSight Biologics S.A. (the "Company"), including with respect to the anticipated future performance of the Company, its subsidiaries and affiliates, and the market in which they operate. They include all matters that are not historical facts. These forward-looking statements can be identified by the use of forward-looking terminology including the terms "developments," "estimates," "expects," "intends," "may," "milestones," "potential," "value," "time to market," "targeting," "on track," "planned," "will," "move to," or other variations or comparable terminology, or by discussions of strategy and funding, as well as the Company's, its subsidiaries' and affiliates' technology, and are based on financial and non-financial information, including projections as to the future regulatory situation and other information and assumptions. Such statements, forecasts and estimates are based on various assumptions and assessments of known and unknown risks, uncertainties and other factors, which were deemed reasonable when made but may or may not prove to be correct. Actual events are difficult to predict and maydepend upon factors that are beyond the Company's control. Therefore, actual results, the financial condition, performance or achievements of the Company, its subsidiaries and affiliates or industry results, may turn out to be materially different from any future results, performance or achievements expressed or implied by such statements, forecasts and estimates. Forward-looking statements, forecasts and estimates only speak as of the date of this forward-looking statement, and no representations are made as to the accuracy or fairness of such forward-looking statements, forecasts and estimates. The Company, its subsidiaries and affiliates disclaim any obligation to update any such forward-looking statement, forecast or estimates to reflect any change in the Company's expectations with regard thereto, or any events, or changes in conditions or circumstances on which any such statement, forecast or estimate is based.

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June 2020 - non confidential

Corporate Overview - Transitioning from R&D to Commercial organization

GenSight at the forefront of Gene Therapy in ophthalmology

• • Publicly traded Biotech company

• • Seasoned management team with strong BioPharma and Financial markets experience

• • Technology platform leveraging disruptive gene therapies in ophthalmology

• • Lead product targets mitochondrial diseases, applicable to broad number of diseases

• • Second compound targets large indications such as Dry Age-related Macular Degeneration

• • ATU granted in France in December 2019

Differentiated Gene Therapy approach

• • Focus on ophthalmological diseases:

  • • Through mitochondrial DNA correction (LUMEVOQ®)

  • • By shaping retinal ganglion cells into photoreceptors (GS030)

• • Using AAV2 as vector with proven safety and efficiency in human as well as well established manufacturing process

LUMEVOQ® (GS010) - Preparing for regulatory submission in 2020 and commercial launch in 2021

• • Strong clinical benefit vs Natural History and/or nadir in 2 completed Phase III studies in rare ophthalmic disease with no/limited competition

• • Commercial strategy and contract manufacturing capabilities close to completion

Established in 2012 / IPO in 2016 EuroNext Paris:

Market Cap (June 11, 2020): Avg 30-day Daily volume: Cash (Mar. 31, 2020):SIGHT € 104m 1.8% of O/S € 12.8m

Investment Case

Targeting the LHON ND4 market with high unmet medical need and no widely approved treatment

• • Disease affects ~15,000/22,000 patients in the US/EU with 800/1,200 new cases each year

• • Commercial strategy and manufacturing capabilities close to completion

• • Bilateral injection priced at €700,000 / patient in French named patient Temporary Authorization for Use

Unparalleled clinical benefit demonstrated with LUVEMOQ™ in Leber Hereditary Optic Neuropathy (LHON) in two Phase III studies

• • +28/+26 ETDRS letters (i.e. over 5 lines on visual scale) improvement vs nadir(1) in the two-Phase III studies

• • Clinically meaningful improvement on all Quality of Life parameters at week 96

Additional opportunities through technology platform

• • Large number of mitochondrial diseases making Mitochondrial Targeting Sequence (MTS used in GS010) a pipeline in itself

• • GS030 in Retinitis pigmentosa and dry-AMD (Phase I/II)

Improvement vs nadir in REVERSE and RESCUE

Seasoned Executive Team

Bernard Gilly Chief Executive Officer

PIXIUM VISION (Since 2011) Chairman of the Board, Founder

FOVEA PHARMA (2005-2009) Chairman & CEO - sold to Sanofi

SOFINNOVA PARTNERS (2000-2005) Managing Partner

TRANSGENE (1992-2000) Chairman & CEO

Ph.D. in biology and bio-economics

Thomas Gidoin Chief Financial Officer

DBV TECHNOLOGIES (2012-2015) VP of Finance

IPSEN (2008-2011)

UK Operations Controller (London) Senior Financial Analyst (Paris)

ERNST & YOUNG (2007-2008) Auditor

Magali Taiel Chief Medical Officer

ProQR THERAPEUTICS (2016-2018)

VP of Clinical Development

ELI LILLY (2004-2016) Medical Department Lead

PFIZER (2001-2004) Medical Advisor

SERVIER (1999-2001)

R&D International Project Manager

MD, Board-certified ophthalmologist

Catherine Cancian

Vice President Pharmaceutical

Operations

GENETHON (2015-2017) Project Leader

SANOFI PASTEUR (1998-2014) Industrial Operations and Regulatory Affairs

Julio Benedicto Vice President Marketing

IMS CONSULTING (2011-2017) Principal

BOOZ & COMPANY (2010-2011) Principal

MONITOR GROUP (1994-2009) Global Account Manager