Mayotte is a French oversea territory. And like almost all french oversea territory it is very poor, but less than the average neighbor countries leading to a lot of immigration which are difficult to control (even though Mayotte is an Island which make it a bit more controllable than Guyana for example). This usually end up in a increasing poverty and unemployment, leading to criminality, aging infrastructure, and public services not being able to handle the demand.

Like a lot of oversea territory, it has some beautiful landscape, but is crippled by the problems above. Living there is very difficult.

EDIT: Note also that I am not blaming immigrant. The problem being that adding more poor people in an already poor territory doesn't solve the problem of poverty. And France unwillingness to treat its oversea territory fairly and really invest in them is the main root of the problem.