PARIS (Reuters) - First Emmanuel Macron blew apart France’s left-right political divide, now the president’s upstart political party looks set to win a commanding majority in parliament, leaving opponents to issue a word of caution.

Be wary of becoming a victim of your own success, they say.

Macron, a head of state who never before held elected office, is on a drive to shake up French politics, backed by a new centrist party of seasoned politicians, entrepreneurs and civil society activists. Perhaps even a bullfighter.

Just a month ago, when the 39-year-old won the keys to the Elysee palace, Macron faced a huge question-mark over his party’s chances of winning control of parliament and thus his ability to push through his reforms to revive the regulation-laden economy.

Now, some opinion polls show him winning the biggest parliamentary majority for a French president since Charles de Gaulle’s 1968 landslide.

That, though, could pose some awkward questions for a party spanning the old left-right divide with a large contingent of political novices: How would he control the majority and avoid dissent within the ranks? And how would he balance political veterans and newcomers in key parliamentary positions?

Frederic Lefebvre, a center-right lawmaker who quit conservative Republicans party on Thursday, said Macron risked undermining his bid to renew French politics if his majority is seen as unrepresentative of the electorate.

“A massive majority ultimately risks standing in the way of Macron’s original mission ... which is to succeed in creating a new political mindset,” Lefebvre told France Info.

Some Macron opponents are calling his future lawmakers “godillots”, or yes men, a label given to De Gaulle’s parliamentarians who were viewed as rubber-stamping his policies. LREM shrugs off the tag.

“It is not a handicap to have life experiences that differ from those who follow a (career politician) path but in reality don’t represent society,” said Christophe Castaner, Macron’s minister for parliamentary relations.

“NASTY FIGHT”

Macron, a former investment banker, wants deeper European integration. At home, where unemployment hovers near double digits, he promises to drive through a pro-business overhaul of the labor code to spur job creation.

Yet a third of voters in the presidential election run-off on May 7 chose his rival Marine Le Pen, who has views diametrically opposed to his. In the first round, only about a quarter of those who voted picked Macron.

So with polls now showing his Republic on the Move (LREM) party could win a majority of 100 seats or more in the 577-strong lower house of parliament, while Le Pen and tax-and-spend hard-leftist Jean-Luc Melenchon’s France Unbowed party could get fewer than 20 seats between them, friction in the country is a concern, Macron’s opponents say.

“If Macron’s candidates win, it will be a nasty fight,” Melenchon told Society magazine.

Melenchon said Macron “lacked the social base” to push through labor reforms that critics say would weaken the traditionally muscular trade unions.

LREM retorts that its candidate list fits its declared aim of making French politics more representative.

“They are men and women, citizens, unionists, business leaders, people who have real experience and who represent a little bit of France. To represent France, it’s a good thing to bring them together,” Castaner said earlier this week.