722017 INTEGRATED REPORT

METHODOLOGY NOTE ON THE ANNUAL REPORTING

PRINCIPLES To manage the implementation of its social, societal and environmental initiatives, control the related risks and promote communications with stakeholders, SUEZ committed to introducing a specific reporting system for these areas in 2003. This system was developed on the basis of recommendations arising from the work performed at international discussion forums like the Global Reporting Initiative (GRI) or the World Business Council for Sustainable Development (WBCSD). It specifically covers all the information required by Article 225 of the French Law of 12 July 2010 regarding the national commitment to the environment (commonly known as the Grenelle 2 Act Article R. 225-102-1 of the French Commercial Code) and by its Application Decrees of 24 April 2012 and of 19 August 2016.

SUEZ operates very different businesses that span a wide variety of contractual forms in the Water and Waste sectors, illustrated by the implementation of very diverse operating models across several thousand sites throughout the world. In addition to constant changes in the Group s operational scope, this very wide range of situations makes determining and stabilising relevant indicators extremely complex, as well as collecting and calculating statistical data. Accordingly, SUEZ has been pursuing its efforts to obtain increasingly reliable data audited by third parties. The aim is to make this non-financial reporting process an increasingly effective guidance tool for supporting the aims of the Group s Sustainable Development and Corporate Social Responsibility Roadmap, as well as a tool used in discussions regarding the ongoing improvement of its overall performance.

SCOPE The figures published in this report refer exclusively to fully consolidated companies, in which SUEZ has operational control. As soon as a company enters the scope of fully consolidated companies, its environmental data is incorporated in full, regardless of the percentage of the equity held. The scope is defined on 30 June of the year of the exercise. Acquisitions taking place after 30 June are not included. This means the WTS BU (created from the acquisition of GE Water's business in September 2017) is not included in the scope of the environmental and health and safety reporting. The employment and economic data for the activities incorporated through the acquisition of GE Water are included on a pro rata basis.

EXTERNAL CONTROLS AND CHECKS Since the 2012 financial year, the external control work entrusted to the third-party independent body has been in compliance with the obligations of Article 225 of the French law of 12 July 2010 regarding the national commitment to the environment (commonly known as the Grenelle 2 Act Article R. 225- 102-1 of the French Commercial Code), namely the following:

a declaration regarding the inclusion of all the information required by Article R. 225-102-1 of the French Commercial Code and its Application Decrees of 24 April 2012 and 19 August 2016 in the Management Report and the Reference Document; a reasoned opinion on the fairness of the information published in the Management Report and the Reference Document, expressing

a conclusion of limited assurance of the fact that the information is presented fairly in all significant aspects.

The environmental, social and societal indicators covered by the conclusion of limited assurance are indicated by specific symbols (X) in the general indicator reporting table on pages 81 to 87. It should be noted that, for the first time since the 2015 financial year, the Group has included its entire "carbon profile" (emissions produced by SUEZ and emissions avoided for SUEZ customers) in its Management Document and Reference Document. The conclusion of limited assurance reached by the independent third party therefore also applies to the environmental information that allowed the calculation of this profile.

Beyond these regulatory obligations, and in keeping with previous financial years in the GDF SUEZ Group and its business lines until 2007, and thereafter in the SUEZ Environnement Group, the SUEZ Group has entrusted the specialist departments of its Statutory Auditors with the following missions for the 2017 financial year: an audit providing reasonable assurance of six calculated environmental indicators based on 124 primary environmental indicators; an audit providing reasonable assurance of ten calculated environmental indicators based on 32 primary social indicators that should undergo audits providing reasonable assurance, and an audit providing limited assurance of eight calculated social indicators; an audit providing reasonable assurance of two community-based indicators. The audited indicators covered by the reasonable assurance are indicated by special characters

(XX) contained in the general table of indicators on pages 81 to 87. The nature of the work carried out and the conclusions of the Statutory Auditors appointed as independent third parties, dated 8 March 2018, are available on pages 76 to 78 of this report.

CONTRIBUTION OF THE ANNUAL REPORTING PROCESS TO MONITORING THE TARGETS IN THE SUEZ ROADMAP Once the data gathered had been processed, the environmental and social reports described opposite were used to determine traceability of the quantified indicators in the Sustainable Development Roadmap 2017-2021.

Furthermore, because the Sustainable Development Roadmap is the framework for a progressive approach, some of the indicators, which are accompanied by targets to be achieved in 2021 according to dedicated action plans, do not systematically cover all the businesses or the entire scope covered by the Group s environmental and employee reports. These restrictions on the consolidation scope have been indicated on a case-by-case basis in the chapters relating to each of the Roadmap s 12 commitments.