French security forces have rejected 13 people who were selected to take part in the torch relay for the Paris Olympics, including some who had committed drugs offences as well as a suspected Islamist, Interior Minister Gerald Darmanin said on Monday.

Around 12,000 people have been vetted after being chosen for the 80-day relay across France which begins in Marseille on May 8 and will finish for the start of the Paris Games on July 26.

"The vetting process has taken place and led to 13 incompatibility notices, meaning a very low rate of 0.10 percent," Darmanin told reporters at a press conference.

He said 10 were for people with "substantial criminal records, mostly for drugs offences", while three others were rejected by the intelligence services for "radical Islam, foreign interference, or links to the Russian-Ukrainian conflict."

The rejections "underline the efficiency of the vetting process and perhaps the plans of some people to disrupt the torch relay from the inside," he said.

The flame will be carried inside a "security bubble" of 100 travelling security forces, comprising motorbike teams, rapid-response forces, anti-drone specialists and anti-terror police.

Darmanin likened the relay through 400 towns to the annual Tour de France bicycle race but "with more originality and difficulties."

He said security forces were on permanent alert for potential terror threats but remained principally concerned by the risk of environmental groups seeking to use the event for publicity.

Noting a video circulating online called "how to extinguish the Olympic flame," he added that activist groups were "a very significant threat and we need to take it seriously."

The torch will be lit in Olympia in Greece, then brought by boat to the southern French port of Marseille on May 8 in a three-masted 19th-century French tall ship called the Belum.

Some media reports have suggested it will finish atop the Eiffel Tower but organisers are keeping its resting place for the duration of the Games a secret.

Olympic relays have been targeted by protesters in the past. French police had to cut short the relay in Paris in 2008 and repeatedly extinguish the flame after protesters against China's human rights record demonstrated against the Beijing Games of that year.