2/ First opinion polls after Macron's calling for snap elections actually suggest that RN and other far right parties actually might very well come on top.
There are reports that opposion Socialist party and left and far left parties have already made electoral pact with explicit aim of preventing RN majority. If this happens, so-called "cordon sanitaire" will, due to specifics of French electoral system, based on runoff voting, be created at the expense of centre right or centre parties, like Macron's Renaissance, which got clobbered by RN on European election few days ago.