If μ is a moderated measure on T, there exists a sequence (μn)n∈N of measures with compact support such that μ=∑n∈Nμn.
By hypothesis, the constant function 1 is μ-moderated. Let us apply Cor. 3 to the case f=1; thus, there exists a sequence (Kn)n∈N of pairwise disjoint compact subsets of T such that 1=∑n∈NφKnμ-almost everywhere. Let μn be the measure on T defined by the measure μKn on Kn (No. 3, Example 2). One knows (No. 6, Remark 2) that μn has compact support, and that μn∙(f)=μ∙(fφKn) for f∈F+(T). Now, f is equal to ∑n∈NfφKnμ-almost everywhere, whence
μ∙(f)=n∈N∑μ∙(fφKn)=n∈N∑μn∙(f).
It follows that μ=∑n∈Nμn (No. 7, Prop. 7).
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.