To understand this, it's important to appreciate the historical cultural factors at work here, as well as the various costs involved.
Traditionally, people would pay be cash, and when they had to pay say a council tax bill, they would go to the Trésor Public and pay it in cash; this is within living memory, and a lot of older folk are mistrustful of banks etc. Also, many people in rural areas have simply never had a bank account.
People prefer to write cheques, as they feel they can control what they pay and when — variable direct debits only came in in France fairly recently, and of course, fixed-amount standing orders are no use for things that vary.
People are VERY mistrustful of giving out details of their bank account, or (heaven forbid!) authorizing companies to take money out of their own accord.
Then on the bank side of things, setting up a beneficiary for making 'virements' can be quite an irritatingly longwinded procedure, and varies from bank to bank.
As for using bank cards, many smaller businesses find that the cost of having a card machine cannot be justified by their tunover — again, it varies widely between banks and which scheme you choose. Plus in general, traders object to having a 'commission' creamed of every transaction — even though it is really only a very tiny percentage!
Thankfully, this is now changing — I'm expecting any day now beggars in the street to be using wireless card machines: "That'll do nicely!"
However, I will fight tooth and nail to keep cash going; I don't at all like the idea of there being a computer trace of everything I do and everywhere I go!