Corollary 3
Tag 01ED, permanent. Cite it as [Bourbaki, Tag 01ED].
Lie Groups and Lie Algebras, chapter IX, § 5. Conjugacy classes
Let H be a Lie group and a compact subgroup of H. Assume that is compact and that satisfies condition (*) of Cor. 2. Then there exists a maximal torus T of such that .
Bourbaki sets the proof directly after the statement, and the corpus does not separate them, so what is above is the statement and its proof together.