Ten of the dead were from Saint Francois d'Assise lower secondary school in Montigny-le-Bretonneux, near Paris, and were on a school study trip.
They were in a party of about 30 pupils, teachers and mountaineers who, despite warnings that the risk of avalanches was extremely high, were last Friday trekking on snowshoes back to base after spending the night in a hut.
Reports said it was the group itself which set off the vast avalanche which swept members of the party down the slope, causing the deaths and injuring 21 others, nine seriously.
Local mountaineering experts expressed astonishment that the group had been allowed to make the hike in such dangerous conditions, and an inquiry was set up immediately into the circumstances of the disaster.
The guide leading the group, Daniel Forte, was arrested over the weekend and later charged with manslaughter, involuntary injury and placing the lives of others in danger.
He had apparently made several serious errors. The route the group was taking was mostly at mid-mountain level in forest which offers protection against avalanches; but Forte took the pupils via a 2,300-metre ridge above the tree line, although they were not competent to tackle high mountain conditions. He allegedly did not advise them to keep far enough apart to avoid overloading the unstable snow and limit the numbers caught if an avalanche occurred. None of the party had an alarm to help rescue workers locate avalanche victims.
They were also approaching the ridge at about 1pm, by which time the sun had warmed the area, softening the snow; some pupils had stripped down to their T-shirts.
Prime minister Lionel Jospin and schools minister Segol ne Royal were among members of the government who went to the scene. The funerals of the victims took place on Tuesday.