If you want to open a business, you're likely to be legally required to open a business banking account. That's because in France, you first have to deposit your shares before setting up an SME.
In the cases of companies with shares (SAS, SASU, SARL, EURL etc.), to be able to register your business, you must write your company's statutes, gather funds and deposit them in the business' bank account.
In theory, companies have the right to transfer the balance to a traditional bank account and close the business account. In practice, however, doing this may lead tax authorities to interpret this balance as a salary.
There are exceptions: micro-enterprises, for example, aren't legally obliged to open a business account. If you decide to create a micro-enterprise, you still need to open another bank account that's separate from your personal one, but it doesn't have to be a business account.
Opening a business account is advisable in any case, given the advantages it offers in terms of managing your business, saving time and avoiding hidden monthly fees. A business checking account will mean easier tax auditing and finance management; it also separates your personal finances from your business books, which may be in your best interest in fiscal terms.
People who have been banned from holding an account with traditional banks can still apply to open checking accounts with payment institutions such as Qonto.
Associations are not obliged to create a bank account either. However, it is absolutely necessary to obtain subsidies, recruit employees, and spend and receive money in ways other than cash.