European Affairs Minister Nathalie Loiseau said the crisis following the banned 1 October referendum had to be resolved through dialogue within Spain.
Catalan President Carles Puigdemont is expected to address the regional parliament on Tuesday.
There has been no sign of a compromise being struck with Madrid.
Economic pressure on the pro-independence camp is rising with three more companies expected to discuss moving their offices out of Catalonia on Monday, sources told Reuters news agency.
These are infrastructure firm Abertis, telecoms company Cellnex and property group Inmobiliaria Colonial.