Micro-entreprise is only a new fuzzy word for auto-entrepreneur. There is no difference, and it is habitually used to refer as the tax regime for this type of entrepreneurs.
To open one, you should simply consider doing your demand on the official website https://www.lautoentrepreneur.fr/
What to know about the status :
- You can have the ACCRE, giving you degressive exoneration of taxes in the span of 3 years (only if you meet certains conditions)
- The tax floor has changed in 2018, it has pretty doubled for all types of enterprise, see here. The mere change is that you can now have collecting and disbursment of TVA if you exceed some revenues thresold
- You have to open a bank account separated from your personal one, but it don't have to be a professional one
Globally, it is pretty easy to handle the administratives task of an auto-entreprise
because you don't have to make an accounting. But as this changed in 2018 with the doubling up of the turnover, if you now exceed 32 270€, you have to pay the TVA and thus make some accounting things that makes the things a bit harder.