About 30,000 police will be deployed across France on Sunday night amid fears of violence after the final results of a snap election in which the far right hopes to gain a majority in parliament.

Gérald Darmanin, the interior minister, said 5,000 police would be on duty in Paris and its surrounding areas to “ensure that the radical right and radical left do not take advantage of the situation to cause mayhem”.

Four people, including one under 18, were arrested after the government spokesperson, Prisca Thevenot, said she and her team had been attacked on Wednesday evening while putting up campaign posters in Meudon, outside Paris.

“Let’s reject the climate of violence and hatred that is taking hold,” prime minister Gabriel Attal wrote on Thursday on X, adding that violence and intimidation had “no place in our democracy.”

Sunday’s decisive second round is expected to result in the far-right, anti-immigration RN becoming the biggest party in parliament, whether or not it reaches the 289 seats needed for an absolute majority to form the next government.

Both the centrist grouping of the president, Emmanuel Macron, and a broadleftwing coalition, have withdrawn more than 200 candidates from the final runoff in a joint effort to limit the far right’s seats. The exact number of seats the far right RN and its allies could win in the 577-seat national assembly is hard to predict, but Harris Interactive polling for Challenges magazine on Wednesday suggested they could take up to 220.