2. The location
In summer, while you are planning your next French class, everything seems easier, especially things like driving, parking and walking. So bear that in mind when you are selecting the location of your French class. How far is it from home / work? Is there any convenient public transport? Will you have to go through busy traffic at a peak time? Is there any parking there? And is it free?
If you course takes place during the day, i.e. late morning or early afternoon, the traffic will be much lighter but the parking might be an issue. If you opt for an evening course, check the commute time to the venue.
It would be a shame if you enthusiastically embarked on a course, to find in November that the commuting is too long and tiring to be sustainable.
Another consideration to take into account when choosing an adult school is the general surroundings. Is it in a busy town centre, with lots of noise which might interfere with the course? Is it in drab surroundings which might bring your moral down?
After all, you wish to join a French course, not to punish yourself. So make sure you start with as many plusses as possible and give yourself a chance to enjoy it.