As said it depends entirely on your personal circumstances, eg are you working or inactive, and how long have you been here. You say 'earn' which suggests you are maybe a part time employee on a low wage or running a business that isn't doing very well, in which case you might be eligible for certain reductions and benefits. If you are, these are normally triggered automatically when your tax form is processed, so you may find that your taxe d'habitation bill is reduced and you may receive forms in the post telling you about things you might be eligible for, and how to apply. You might also be eligible for free healthcare, CMU-C - ask at CPAM. But if you really are trying to survive on that level of income I would suggest you see the assistante sociale and ask about things like food parcels and cheap electricity, because frankly I don't see how a couple can possibly live on that, it sounds like a desperate situation and I think you will need a stronger safety net than the state will provide.