Rajoy on Saturday took the unprecented step of opening the process of firing the Catalan regional government so that Madrid can take over its functions, following a referendum that he considers illegal backed independence from Spain.
Catalan regional president Carles Puigdemont hit back, accusing Rajoy of the “worst attack on Catalan institutions since the dictator General Franco ordered the end of our autonomy” and thousands of pro-independence supporters demonstrated against the move almost as soon as it was announced.
"What's important in this matter is that there is the rule of law that must be expected that this should be the central point of reference for European construction," Le Drian told the Journal du Dimanche newspaper.
"Once you leave the constitutional framework in an EU member-state, you are in a situation of dangerour disruption."
Rajoy also said that a regional election will be held in Catalonia within six months.
"I hope they will clarify the situation and open a constructive dialogue," Le Drian said.
"Dialogue is always better than confrontation as lons as calms has been restored and it takes place within a legal context," he added.
During the week President Emmanuel Macron backed Rajoy in his stand-off with the Catalan regional government, as did German Chancellor Angela Merkel.
The European Union has also supported Madrid and declined to mediate in the crisis.