FLE is French Lessons for Etrangers & is usually on offer, if at all, someone's first year (whichever class it is) in the secondary school system. Only available if there is someone FLE qualified with space in their timetable.
The dispositif anti-décrochage (anti-drop-out-system) is designed to stop people at risk of dropping out of the system doing just that & leaving school or education from home with nothing, that's why it is usually for people who acted the goat at lycée, ignored all our recommendations and didn't do any work, wasted their time & ours & failed their Bac to nobody's surprise but their own & then realised, once in the real world, that we aren't all a bunch of idiots wanting to make their lives a misery. Lower down in the system you get classe-relais sometimes within a collège, sometimes located outside a school (less off-putting for some but usually not so well resourced).
By 3ème someone shouldn't be needing help to revise - étude in the evenings at school is designed simply as a time for pupils to do their work independently, they are under supervision so they aren't messing about, but they aren't talked through it or anything after 6ème because they are expected to be increasingly autonomous and self-motivated. If they aren't, lycée is going to be a BIG shock for them.
For devoirs in collège they will have a mix of new stuff to do, things to write, things to learn and at the very least their leçons of the day to read through and absorb. Obviously if there is a one-off difficulty the pion will probably try to help if asked but they aren't there to be tutors. It is the same as when I was at school in GB - you had half an hour's supervised prep in the morning between breakfast & lessons starting & then 2 hours supervised prep in the evening after supper, but obviously you have to use your own time to work as well.
You can buy a book of 'Annales du Brevet' which has past papers in it for the examined subjects (there's nothing for the continuous assessment ones) and work through them, there is usually a key at the back for correction. This may help with revision, in terms of understanding what the questions are actually asking the candidate to do, quite often pupils don't really pay enough attention to this when it is explained in class (& sometimes teachers take it for granted that they have understood, when they haven't).