Guide held in police custody and an investigation launched into possible manslaughter and unintentional harm after tragedy in Entraunes area.
Police say a Dutch national was killed in the avalanche at Alpine resort of Valfréjus on Wednesday, with two other Dutch citizens also missing.
The victims were buried by a 400-metre wide avalanche near the ski resort of Tignes where search and rescue operations continued Monday afternoon for possible survivors from the group of skiers who are believed to have numbered nine people.
A woman of British-Polish nationality and another from Slovakia were swept away with their German male guide as they climbed the Mont Blanc.
Six other members of a group of about 50 troops were injured after an avalanche hit their skiing exercise at an altitude of more than 2,000 metres.
The teacher led his pupils onto a closed black piste where two of the teenagers and a nearby tourist died after becoming engulfed in an avalanche.
Five members of a school ski party were still misssing hours after the avalanche at the Deux Alpes resort, while four others were seriously injured.
The avalanche hit three groups of climbers, leaving one survivor seriously injured, on the Dôme de Neige des Ecrins mountain near Pelvoux.
The experienced skiers, four men and two women aged between 58 and 73, were trekking at 7,900ft when they were swept to their deaths.
Local official is furious after climber Paul Sweeny told US TV he climbed the mountain with his two young boys when an avalanche struck.
Three Britons, three Germans, two Spaniards and one Swiss climber died in the tragedy on the slopes of Mont Maudit.