Proposition 6
Tag 091C, permanent. Cite it as [Bourbaki, Tag 091C].
Integration, chapter V, § 3. Integration of positive measures
For a mapping of T into a topological space F to be universally measurable, it is necessary and sufficient that be measurable for every positive measure on T with compact support.
The condition is obviously necessary; on the other hand it is sufficient, because every positive measure is the sum of a family of measures with compact support (§2, No. 3, Prop. 4): the statement then follows from Prop. 2 of §2, No. 2.
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.