Mistakes and disasters happen, unfortunately the safety we have while flying today has been written in blood, but there is no major understaffed ATC and undertrained pilots in general as mentioned.

15 down to 12 in 5 years with more traffic is not out of the question with advancements in technology but of course, if there is a report that shows understaffing then absolutely it should be addressed straight away and it will be, by the French government.