Newly-inaugurated French President Emmanuel Macron appointed a conservative prime minister on Monday in a move to broaden his political appeal and weaken his opponents before legislative elections in June.

Edouard Philippe, 46, a lawmaker and mayor of port city Le Havre, is from the moderate wing of the main centre-right The Republicans party and will be a counterweight to former Socialist MPs who have joined Macron's cause.

Elysee secretary-general Alexis Kohler made the announcement on the steps of the presidential Elysee palace.

Mr Macron has vowed to end the left-right politics which have dominated France for decades, and his start-up centrist Republic on the Move (REM) party, which is just a year old, needs to find a wide base of support for the parliamentary elections.

Mr Philippe is a close associate of former prime minister Alain Juppe, who leads the moderate wing of The Republicans and has indicated that he favours helping Macron. His appointment could draw more defectors from The Republicans.