Ex-French prime minister Manuel Valls has said France's Socialist party "is dead" and he wants to run under the banner of President-elect Emmanuel Macron's political movement in June's parliamentary elections.
Mr Valls, a centre-leaning politician in favour of relaxing labour protections, had already thrown his support behind Mr Macron before the presidential election after losing to Benoit Hamon in the Socialist primary.
Mr Valls told RTL radio that Mr Macron's victory over far-right leader Marine Le Pen in the presidential run-off on Sunday was a blow to populism in Europe, and gave a "terrific" image of France abroad.
Mr Valls said that "I will be a candidate in the presidential majority and I wish to join up to his movement, the Republic on the Move".