France charged on Friday three members of a neo-nazi group on suspicion of planning an attack against a masonic lodge, a judicial source said.
The three suspects, two men aged 29 and 56 and a woman aged 53, were placed in pre-trial detention under charges of "criminal terrorist association," the source added.
They were arrested on Tuesday as part of a preliminary investigation opened in February by France's anti-terror prosecutor on a small ultra-right group named "Honour and Nation."
Investigators intercepted communications between the suspects suggesting they were conducting research on explosive substances and had scouted locations for possible attacks.
However, their projects did not seem imminent.
Three other people arrested on Tuesday were released without prosecution at this stage.
A source close to the case told AFP that some of the suspects were in contact with Rémy Daillet, a prominent figure of the French conspiracy movement who lives in Malaysia.
Daillet is suspected of having contributed to the organization of the kidnapping of an 8-year old child last month.
Several other anti-terrorism investigations linked to ultra-right movements are currently underway in France.
Last month anti-terror prosecutors requested a trial for nine members of a group calling itself OAS that was dismantled in 2017, suspected of targeting senior politicians or French Muslims.
Another organisation suspected of planning attacks on Muslims, AFO, was taken down in 2018, the same year as still another group believed to have been preparing an attempt on President Emmanuel Macron's life.
Further anti-terrorist probes relate to a neo-Nazi group suspected of targeting Jewish and Muslim places of worship and to a white supremacist who admired the perpetrator of the 2019 attack on mosques in New Zealand city Christchurch.