French Prime Minister Jean-Marc Ayrault tenders designation

French Socialist Prime Minister Jean-Marc Ayrault on March 30, 2014 at the Hotel Matignon in Paris

PARIS—French Prime Minister Jean-Marc Ayrault tendered his resignation and that of his government to President François Hollande on Monday, a day after the ruling Socialist Party suffered a stinging setback in the final round of nationwide local elections.

In an effort to bolster his agenda, Mr. Hollande is expected to select Manuel Valls, a Socialist heavyweight and France’s popular Interior Minister, as his new premier.

Mr. Hollande is expected to confirm his choice of a new prime minister when he delivers a brief address on national television later Monday.