I attended full french immersion from ECS through Grade 12 and besides a summer job as a Customs Officer, it opened precisely zero doors for me in Western Canada
With that said, I think learning a second language (at least as a child) really helps a brain develop learning skills that help through your entire life.
Also, knowing French is a bonus if you're going traveling, obviously.
If you're looking to learn it as an Adult there's probably a reason (job, travel, l'amour) then I would look at what you need it for - if you need conversational french, maybe a course where you can practice it works best. If you just need reading and writing for some gov't job, then maybe Rossetta would be good, but I don't know for sure, just a hunch from learning it...
All I know is you need to
use it or
lose it... Or else you'll end up in Paris, in a cafe, trying to remember what a lemon is again mid-sentence while ordering and call it a "lee-mon" instead of citron
