Roleplay with GPT 4o! Write it in a novel-like format with quotation marks and first-person speech! For instance:
I walk over to the counter and lean over it, looking at her. "So, wanna go out and do something?" I ask. (Except with your text in French, obviously. Use Google Translate if you need to - as long as you're learning, that's not cheating. Be aware that GPT's character tends to automatically "know" anything you write at all. Even your character's internal thoughts. Use that knowledge as you will.)
After that, if you want a longer-term roleplay (days instead of hours), you can do that too. But pay attention, because that's where it gets a little trickier. GPT has a problem I call "style drift" - gradually, over the course of longer conversations, GPT's formatting style drifts towards something choppy, with fragmented lines and a horrible abuse of bold and italic text. Maybe you can put up with it, but I can't stand it. So, usually, I end the roleplay after 4000-12000 words (NOT counting the original prompt) - which usually covers a scene or two.
Paste the following text into GPT (GPT o1, preferably, because that has the best results):
Close to the bottom of your original prompt, you'll find a section that shows how each person feels about you. Update that with the numbers that GPT gives you - in a document on your own computer. Don't read the rest of the file! That's cheating! Discover your main character naturally. She's got a rich backstory personal history, and learning it through roleplay is a lovely experience.
Then, use this prompt (preferably with GPT 4.5, but 4.0 works well enough too):
Close to the bottom of your initial prompt file, you'll find a section that says "Things that have happened since our first meeting - summaries from past sessions" Just paste that in there, in chronological order with the newest bit at the bottom. When you're ready to roleplay again, repeat the process, posting the initial prompt, then a starter post that includes this line, just to make sure GPT remembers:
And you're good to go! Enjoy learning French! (Ideally supplement this with some other form of learning!)