Source-Seine
It was formed on 1 January 2009 when Saint-Germain-Source-Seine was merged with Blessey . 
<triplet> Saint-Germain-Source-Seine <subj> Source-Seine <obj> part of <triplet> Source-Seine <subj> 1 January 2009 <obj> inception <triplet> Blessey <subj> Source-Seine <obj> replaced by