Do UK residents need a passport to go to France?

Question

and what about getting back into the UK on our return?!

Answer 1

You need a passport as UK nationals do not have ID cards. Both UK and French customs officers are waiting for you.  

Answer 2

EU nationals have freedom of travel and the right to abode within other EU nations without a visa or immigration controls; but you need to prove eligibility with a government ID card or Passport. Since the UK government doesn't issue ID cards you need a Passport yes.

If you are a resident but not a citizen you will need a passport and possibly a visa/background check depending on your nationality.