IIRC, Anjouan and Mohéli authorities wanted to join back France in 1997, if France accepted, France would became bigger, and the butterflies will be minimal, but it will be a little trick since I only add two island to France, if you want a "greater" France without changing other border you could also haveBelgium split about the Bruxelle hal vilvorde issue during the 2000/2010 years, then Wallonia authorities could ask to join France, Catalonia could also secede to Spain and ask to join France because they couldn't survive alone.
PS : France could also have a lesser decolonisation.
PS : France could also have a lesser decolonisation.