The relatives of four French hostages kidnapped two-and-a-half years ago in northern Niger protested across France on Saturday demanding their release.
"900 days, that's enough, it's time they return," chanted hundreds of people who gathered in the cities of Paris, Marseille, Nîmes and Nantes.
Marc Feret, Pierre Legrand, Thierry Dol and Daniel Larribe were taken on 16 September 2010 at Arlit where they worked for nuclear group, Areva.
"Concerns have heightened since the beginning of Operation Serval (the intervention of the French army in Mali), today their lives hang by a thread," said Frédéric Cauhapé, the brother-in-law of Marc Feret in Marseille. "Too much talking, too much time lost, too many missed opportunities."
"We want to remind the President of the Republic that they called for help seven months ago (in a video released by Al-Qaeda in the Islamic Maghreb - AQIM) and he promised to bring them home safely." he added.
"The hostages could be in the current conflict zone, that's what we're worried about. We're not saying that the intervention wasn't necessary but we also need to think about the hostages. We have to proceed with caution because they could become victims of enemy or friendly fire," said Christine Cauhapé, Mr Feret's sister.
French Defence Minister, Jean-Yves Le Drian, said on 4 March that all suggestions were that the hostages held in the Sahel were alive.
"The current events are distressing us because we're worried about deadly fighting in the mountains of northern Mali," said Françoise Larribe, the wife of Daniel Larribe in Nîmes, who was a hostage for five months before being released. "But we are filled with hope they'll return."
The French military intervention in northern Mali began on 11 January this year.