First, you must pay a lawyer or formation agent to write and register your by-laws. Next, you must seek an introduction to a bank manager. With that secured, you get to draft a book report of a business plan. This is tedious and pointless. Once completed, the bank manager reviews it. (They will also ask for lots of personal documents, each requiring expensive notarization.) If they approve, you get a business bank account. Into this account you must deposit no less than €4,000. Unfortunately, these funds are frozen until you get your extrait Kbis. That won't happen for at least two weeks.
Now you have to buy an ad in a French newspaper. These are expensive. After a week or two, papers will arrive in the mail. You take these to the Commercial Court, where a bunch of agencies on different floors will stamp them. With those stamped papers in hand, your €4,000 will be unfrozen. (Usually. On the next business day.) Finally, you have to appoint a French accountant. They continually monitor your business and continually charge you fees. Now you can business!
Meanwhile, in Delaware, 24 hours and a few hundred dollars buys you an LLC. A bank account, set up online or in person, can get you going the next day.