Corollary 2
Tag 096C, permanent. Cite it as [Bourbaki, Tag 096C].
Integration, V, p. 76, § 7. Integration with respect to an induced measure
Let g be a complex function defined on T and locally -integrable; the restriction of g to X is then locally -integrable, and
This follows at once from Th. 1, applied to the functions (), and the definition of the measure induced on X by a complex measure (Ch. IV, § 5, No. 7).
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.