I’m sure you have loads of questions about the Fide exam. So let’s dive in.
Why do foreigners need to take the fide exam? Which Permis holder
The answer lies in Swiss law. The Foreigners and Integration Act or la Loi sur les étrangers et l’intégration (LEI) and Federal law on Swiss nationality or la Loi fédérale sur la nationalité suisse (LN) make the fide exam mandatory. Who needs to sit what level is quite complicated though so take a look at the picture.
If you have recently arrived to Switzerland and you are a Permis F or Permis B holder the level required of you is the most basic possible: oral A1 or beginner level French exam. At the exams they expect you to be able to react to a situation with a few sentences.
If you apply for or renew your Permis Cthen you are expected to cope with the same situations in a more proactive manner at A2 or B1 level. You can ask questions, answer, confirm, express in the same situations while at A1 level you answer questions or ask for repetition.
Finally, if you want to be naturalized and be a proud Swiss citizen, you must be able to express yourself at B1 level when speaking and A2 level when you are writing.
Are you confused about what does it actually mean A1, A2 or B1?
First, the big difference between levels is knowledge of vocabulary. At A1 level you have 300 words you can actually pronounce/use and 600 you understand, at A2 level you have 600 words you know how to pronounce and 1200 words you understand, at B1 level you have 1200 active words and 2500 words you understand. Easy peasy right? If you use my method, you bet it is!

