- Duolingo(don't do it for more than a few months)
For beginners
- https://www.languagetransfer.org/free-courses-1#french
For all others, some sort of immersion approach is the only way if you don't live in the country. Figure out the general approach below and adapt for your target language.
- AJATT http://www.alljapaneseallthetime.com/blog/all-japanese-all-t...
- TMW https://learnjapanese.moe/
- Refold https://refold.la/