[seren]

The specific issue with Mayotte is that the other half of the archipelago has chosen to remain independent [1].

So on a very small territory you have a third world country, Comoros, and a piece of the European Union, where, even if it is not on par with continental Europe, has a much higher quality of life.

So there is a quite large influx of immigrants from Comoros, and this is hard to manage for such a small island.

[1] In 1974, France organized a referendum for self-determination in the archipelago in which the population except in Mayotte voted overwhelmingly in favour of independence. Following the unilateral declaration of independence in 1975, France maintained sovereignty over Mayotte. The three remaining islands formed the Etat Comorian, which later became the Federal Islamic Republic of the Comoro Islands.