I think it’s great that you want to learn some more French before your trip. French is difficult to pronounce, but if you work at it, you’ll get better.
A couple of obvious points to consider when you’re figuring out how you’ll do this:
1. Choose a format that works for you.
2. You have to put in the time to make meaningful progress.
3. Don’t be afraid to make mistakes.
I have used Pimsleur for a couple of languages and its format works for me. The two things I don’t like about Pimsleur is that it doesn’t have a written transcript and it isn’t systematic about grammar. I have bought a language course textbook to supplement. (I’m learning a different language so I can’t recommend this for French.)
I used Pimsleur for Polish for about 3 months (I finished about 30 lessons — I have to repeat several times to get it to stick) and was able to conduct simple transactions such as paying entrance fees in Polish.
You have to be disciplined to make progress. I like the flexibility of being self taught (with Pimsleur), but a French class might work better for you, if the social aspect is what keeps you motivated.
Good luck!