Thirty-two passengers, mostly if not all Portuguese nationals from Vila Nova de Foz Coa and Penafiel, in northern Portugal, were travelling on the coach belonging to national company Rota das Gravuras.
Many of the Portuguese were emigrants in Switzerland who were returning following Christmas holidays in their homeland.
The tragedy unfurled during the early hours of Sunday morning as the bus was travelling through France, on the way from Portugal to Switzerland.
It happened on the Route Centre-Europe Atlantique (RCEA) road, which, according to regular international drivers, is notorious for its long, straight monotonous stretches.
Early reports quoting French officials suggest a slippery surface coupled with an inadequate speed may be the main causes behind the accident.
They also stated that among those seriously injured was a two-year-old baby.
Portugal’s State Secretary for Communities, José Luis Carneiro, travelled to France following the crash and visited the injured Portuguese nationals during the course of Monday morning in Lyon.
He also intervened to help speed up the process of getting the bodies of those who lost their lives in the crash back to Portugal.
French newspaper Le Parisien described the accident as the worst in France since March 2016, when 12 Portuguese citizens died on that same road following a head-on collision between a people-carrier and a lorry.
Last year an estimated 270,000 Portuguese nationals were living and working in Switzerland, and form the country’s third largest foreign community.