"The rules of the stability pact do not stop member states from defining their priorities. We understand that the priority is security," EU economic affairs commissioner Pierre Moscovici told a news conference.
Moscovici, the former French finance minister, said the tough budgetary rules imposed by Brussels after the eurozone debt crisis were "neither rigid nor stupid, they are capable of dealing with situations.
"It is in that spirit that we are in discussions with the French government."
"We have to do this and Europe should understand this," Valls told France Inter radio.
"It is also time that the EU, the European Commission, understand today that this battle concerns France, and also Europe."
The show of fiscal solidarity came just hours after EU defence ministers unanimously backed a French request for military assistance in the wake of the Paris attacks.
