Like most administration in France, it can be bit of a bind but if the paperwork is properly prepared it usually just flows. Once a Permis de Construire is submitted a tacit approval is granted after 60 days if no objections are raised. if one is raised, the response that is sent resets the 60 day clock.
So when I was asked to submit further details on 7th February, the clock reset from that date (to 7th April). In addition, the authorities only have a 30 day window to request further information so today, that first hurdle was passed. They have to work with the information I have submitted now. It does not mean approval but it would be surprising if an objection was now raised. So, April 7th becomes the next important land mark.
Here is a taster of the revised plans submitted.