Proposition 9
Tag 09JK, permanent. Cite it as [Bourbaki, Tag 09JK].
Integration, chapter VIII, § 3. Convolution of measures on groups
— For convolution, is a left module over , while and are left modules over . This follows from Prop. 8, and from §1, Props. 1, 3 and the Cor. of Prop. 5.
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.