Compagnie de Saint-Gobain

Prospectus • Aug 24, 2018

Prospectus Supplement n° 1 dated 24 August 2018 to the Base Prospectus dated 13 July 2018.

COMPAGNIE DE SAINT-GOBAIN

(incorporated in the Republic of France) EUR 15,000,000,000 MEDIUM TERM NOTE PROGRAMME

This Prospectus Supplement n° 1 (the "Prospectus Supplement") supplements the Base Prospectus dated 13 July 2018 (the "Base Prospectus") and constitutes a prospectus supplement for the purposes of Article 16 of Directive 2003/71/EC of the European Parliament and the Council (the "Prospectus Directive"). This Prospectus Supplement has been prepared to incorporate by reference the Issuer's consolidated financial statements for the six months ended 30 June 2018 and auditors' review report thereon.

This Prospectus Supplement constitutes a supplement to, and should be read in conjunction with the Base Prospectus. Except where the context otherwise requires, the terms defined in the Base Prospectus have the same meaning when used in this Prospectus Supplement.

Saint-Gobain accepts responsibility for the information contained in this Prospectus Supplement. To the best of its knowledge (having taken all reasonable care to ensure that such is the case) the information contained in this Prospectus Supplement is in accordance with the facts and does not omit anything likely to affect the import of such information. Saint-Gobain's legal name is Compagnie de Saint-Gobain. It is a French société anonyme governed by Articles L. 210-1 et seq, of the French Commercial Code, with its head office at Les Miroirs, 18, avenue d'Alsace, 92400 Courbevoie, France (telephone number: +33(0)1 47 62 30 00). It is registered with the Nanterre Trade and Companies Registry under no. 542039532 (activity code APE 741J), Siret number 54203953200040.

To the extent that there is any inconsistency between (a) any statement in this Prospectus Supplement and (b) any other statement in the Base Prospectus, the statement in this Prospectus Supplement will prevail. Except as disclosed in this Prospectus Supplement, there has been no other significant new factor, material mistake or material inaccuracy relating to information included in the Base Prospectus since the publication of the Base Prospectus.

DOCUMENTS INCORPORATED BY REFERENCE

The following documents shall be deemed to be incorporated in, and to form part of, the Base Prospectus:

• The Issuer's unaudited consolidated financial statements for the six months ended 30 June 2018 and auditors' review report thereon, which have been filed with the Financial Conduct Authority and which are included in the half-year financial report for the six months ended 30 June 2018 (the "Half-year Financial Report 2018").

Any documents themselves incorporated by reference in the documents incorporated by reference in this Prospectus Supplement shall not form part of this Prospectus Supplement for the purposes of the Prospectus Directive.

Any statement contained in the Base Prospectus or in any of the documents incorporated by reference in, and forming part of the Base Prospectus shall be deemed to be modified or superseded for the purpose of the Base Prospectus to the extent that a statement contained in any supplement thereto, including this Prospectus Supplement, or in any document subsequently incorporated by reference, including the documents incorporated by reference by this Prospectus Supplement, modifies or supersedes such statement (whether expressly, by implication or otherwise). Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute part of the Base Prospectus.

For ease of reference, the table below sets out the relevant page references for the English language version of the consolidated financial statements of the Issuer for the six months ended 30 June 2018, together with the English translation of the auditors' review report thereon. This English language version is a direct translation of the French language version of such documents. The nonincorporated parts of the documents incorporated by reference are either not relevant for investors or are covered elsewhere in the Base Prospectus.

Issuer's Unaudited Consolidated Financial Statements for the six months ended 30 June 2018 and Auditors' Review Report thereon

Consolidated Balance Sheet Page 12 Half-year Financial Report 2018
Consolidated Income Statement Page 13 Half-year Financial Report 2018
Consolidated Statement of Recognized Income and Expense Page 14 Half-year Financial Report 2018
Consolidated Statement of Cash Flows	Page 15 Half-year Financial Report 2018
Consolidated Statement of Changes in Equity Page 16 Half-year Financial Report 2018
Notes to the Consolidated Financial Statements	Pages 17 to 42 Half-year Financial Report 2018
Statutory Auditors' Review Report on the Financial Statements for the six months ended 30 June 2018	Pages 43 to 45 Half-year Financial Report 2018

Copies of documents incorporated by reference may be obtained from (i) the website of the Issuer and (ii) the National Storage Mechanism (http://www.morningstar.co.uk/uk/NSM).