Sorry, but Les Républicains are not “center-right”, they are definitely very-right, they campaign on the same topics than the extreme-right and share a lot of points in their programs.
The new Front Populaire regroups a fairly wide variety of parties, from the the far left revolutionary communists like NPA, radical left with PCF and LFI, until the center like Les Socialistes (social Democrats) and Ecologists. Last Sunday, they were divided and dragging each other in the mud, today they have 1) signed to campaign as one, 2) decided the candidates for each county, 3) agreed on a very detailed common program for the next 2~3 years.
The vote takes place on 30th of June, therefore the political landscape of France will continue to shift frenetically for the next 2 weeks at least.