Greenpeace activists have abseiled down the Eiffel Tower to remind voters of France's national motto "liberté, égalité, fraternité'', ahead of the country's presidential election.

The banner, which also read "resist", urged voters to vote against far-right candidate Marine le Pen and the Front National in the final round of the election on Sunday.

Jean-Francois Julliard, CEO of Greenpeace France, told public radio station Francinfo: "We wanted to say we are against the rise of nationalism and authoritarianism in France and in other countries. This is our way of reminding everybody they all need to mobilise to defend these values of liberty, equality and fraternity."

A dozen Greenpeace activists were detained for questioning, police sources said. Paris's police chief called emergency talks on security after the incident in broad daylight. France is deploying extra police for voting day on Sunday.

The Greenpeace action came on the final day of campaigning before Le Pen faces off against centrist Emmanuel Macron in the ballot on 7 May. Macron is tipped in polls to win and become France's president.

Earlier this week, Macron and Le Pen clashed over immigration, security and Europe in the final televised debate before the second round of the election. The two candidates came to a head over national security ­– a loaded issue in a country where more than 230 people have been killed in terrorist attacks since 2015.

A viewers' poll and the French media declared Macron the most convincing candidate after the two-hour debate.

Images live de la banderole #resist de @greenpeacefr dÃ©roulÃ©e sur la Tour Eiffel pic.twitter.com/SRnhlNMiMQ — Emery DoligÃ© (@EmeryDolige) 5 May 2017

Immense respect et Ã©norme coup de chapeau Ã nos activistes, qui ont escaladÃ© la Tour Eiffel pour rappeler avec force nos valeurs.#Resist pic.twitter.com/EAjv6QC5kc 5 May 2017

"FraternitÃ©" : pour une sociÃ©tÃ© humaniste et solidaire, qui ne dÃ©signe pas de boucs Ã©missaires #Resist pic.twitter.com/83pSZYetU0 — Greenpeace France (@greenpeacefr) 5 May 2017