The five were diagnosed with the virus after sharing lodgings with a fellow Briton who had apparently caught it in Singapore.
The group had been staying in two apartments in a ski chalet in the Haute-Savoie region in the eastern French Alps when they were visited by a Briton who had been in Singapore and was found to have the virus when he returned to the UK at the end of last month.
The French health minister Agnès Buzyn said none of the patients were in a serious condition. She described the new outbreak as a “cluster, grouping around one original case”.
Jean-Yves Grall, the head of the regional health authority, told journalists the child lived in the ski resort with their parents and two siblings. The child’s mother was in the UK taking exams and the children were with their father. The six other Britons were in a second apartment in the same chalet. He did not give details of where the visitor believed to have brought the virus from Singapore had stayed.
The local health authority is disinfecting the building and is searching for anyone who might have come into contact with the group.
Grall said the infected child had attended school in Les Contamines-Montjoie and had recently spent a day at a second school in the nearby town of Saint-Gervais-les-Bains.
He said the schools would be shut next week as the authorities tried to determine with whom the child had come into contact.