Hollande seen winning parliament while UMP (Sarkozy's party) could implode
Socialist Francois Hollande can expect a left-wing parliamentary majority if he wins Sunday's presidential runoff, and the far-right National Front could shake President Nicolas Sarkozy's conservative UMP party to its foundations.
If Hollande is elected, as all opinion polls show, history suggests voters will grant him a working majority in legislative elections on June 10 and 17, as they have each time a new president has just been installed. The only doubt is whether his centre-left Socialist party would have an absolute majority or need support from Communist or Green deputies to pass laws.
Sarkozy's UMP party, the dominant force in French politics for a decade, could crack under pressure from a resurgent far-right as factions feud over whether to shun or embrace backers of Marine Le Pen's anti-immigration National Front (FN). If the FN replicated Le Pen's 17.8 percent score on the first presidential ballot on a high turnout, it could split the right-wing vote in more than half of the 577 constituencies, making it easier for the Socialists to beat Sarkozy's UMP party.
This raises an existential question for the UMP, formed to unite France's quarrelsome centre-right movements after a scare in 2002 when Le Pen's father muscled his way into the presidential election runoff against Gaullist Jacques Chirac. "There is a risk of the breakup of the UMP," said Stephane Rozes, president of the CAP political consultancy.
Some on the party's right flank are keen to end the quarantine around the National Front while the main party leaders have flatly ruled out any electoral or government alliance with Le Pen or her party.
http://www.reuters.com/article/2012/05/03/us-france-election-parliament-idUSBRE8420IS20120503
If Sarkozy's conservative party were to "breakup" could the republican party be far behind? 
Unfortunately there is a huge difference between France's multiparty system and our two-party setup. And an implosion of the UMP would undoubtedly strengthen the far-right National Front's influence in French politics.