French authorities have filed preliminary charges of terrorism against a French citizen extradited from Bulgaria and linked to the two gunmen who conducted the deadly attack against satirical magazine Charlie Hebdo earlier this month, international newswires reported.

Fritz-Joly Joachin, 29, was extradited from Bulgaria to France on Thursday to face charges of participating in an organized crime group with aims to prepare a terrorist act, and seeking to join extremist fighters in Syria.

In France, he was ordered behind bars for at last four months pending further investigation.

According to French police, Joachin was an associate of the two Kouachi brothers, who killed 12 people in an attack against the Paris headquarters of Charlie Hebdo on 7 January.

Joachin, a Muslim convert of Haitian origin, was detained in Bulgaria on an unrelated European arrest warrant on 1 January while trying to cross into Turkey at Kapitan Andreevo checkpoint.

While in Bulgaria, Joachin admitted to have known the Kouachi brothers but said he had not seen them since July 2014. He also said he had spoken to one of the brothers over the phone two or three times last year.

He was extradited after Bulgarian authorities granted a European arrest warrant issued by a Paris court against him earlier this month. Joachin had said he was not guilty and that he would like to return to France where he had a job waiting for him.

The construction worker, who had no previous criminal convictions, was travelling with a man who was allegedly part of a Islamist network in Paris, according to his European arrest warrant.

Joachin told French judges he had been travelling to Turkey on vacation - not to join fighters in Syria.