The Socialist Emmanuel Grégoire has been elected mayor of Paris, beating the former rightwing minister Rachida Dati, with Marine Le Pen’s far-right, anti-immigration National Rally (RN) failing to take key cities targeted in Sunday’s second round of local elections.

Grégoire took a victory bike ride with future councillors in Paris on Sunday night to show that the French capital would continue its pro-cycling and environmental policies.

“There’s lots to do and we’ll start tomorrow morning,” said the Socialist MP who has a long record at City Hall where he worked with the former Socialist mayor Anne Hidalgo.

After running on a united left ticket that included the Greens, Grégoire said there were several priorities for the French capital.

He said: “I’m thinking of the most fragile people, those who will sleep on the streets tonight. I’m thinking of children who are suffering … all the most vulnerable who need the left.”

He said he had “an immense responsibility” to Parisians.

Grégoire was projected to have won with about 52% of the vote. This marked a clear win against Dati, who served in government under Emmanuel Macron and Nicolas Sarkozy and had sought to win the French capital for the right after 25 years of it being governed by the left.

During the campaign, Grégoire, 48, had warned that Dati would turn the capital into “a Trumpist laboratory of the alliance between the right and far right”.