I'm not an expert on the topic and I'm not saying France isn't milking its former colonial legacy for all it's worth (it is) but color me skeptical that all of those countries would be keeping the Franc CFA if it was such a bad deal for them. I can see pretty obvious advantage for a developing country to be using a currency that's stable and backed up by the treasury of a developed one. That might have some negative long-term consequences for these countries' development, but there's also a clear short- and medium-term benefit.
Also, not that negates what you said about propping up corrupt regimes, but I should point out that France also prevented Mali from becoming another ISIS and most people there is pretty grateful for that as far as I can tell.
Di Maio is talking out of his ass, as he always does.
The CFA Franc prioritizes exports of natural resources to France instead of inter-regional trade, hampering regional and domestic development in the African Francophone sphere. It has been proven again and again, from the DRC to Iraq, that such an export reliant economy with little diversity, especially the need for human capital, is a hindrance to the stability and independence from outside and inner pressures.
Be wary of French interventions, as in most cases the payment to France is unquestionable loyalty. Look no further than Cameroon using their counter-terrorism aide to instead stave off popular uprisings in Ambazonia, or the removal of anti-French resistance in the Ivory Coast. Stability is so far limited in definition to French leaders to mean the continued subservience of the African Francophone region.
Don’t confuse my intentions, Di Maio is talking out of his gassy behind, but he has a point in this case.