That sparked howls of disapproval from automobile groups, who said the measure was another wheeze to fleece motorists via speed traps and would even cause dangerous and un-ecological traffic jams.
Some analysts say the speed limit was the initial catalyst for the gilet jaune (yellow vest) movement, even before resistance erupted against President Emmanuel Macron's decision to slap new green taxes on diesel and petrol in the New Year. Some 78 per cent of the French oppose the changes, according to one recent poll.
Announcing the road deaths drop, Edouard Philippe, the prime minister, said the effects of the new restrictions were "without ambiguity" and that 116 lives had been saved because of them. "We took a decision that we knew was unpopular," he said. "We are proud of the results, of the lives saved."
But the French drivers' organisation "40 millions d'automobilistes" pointed out that road deaths had already started to fall at the start of 2018 before the new speed limit cut was implemented. "Death rates had generally been slowing down, even a year before the speed limit," said the motorists' group.
In a nod to anger over the restrictions, Philippe said it was "legitimate to discuss the issue" in the current "great debate" launched by Macron in a bid to defuse the gilet jaune revolt.
"But it would be mad to lower the level of ambition," he went on. "I wouldn't want measures to be taken that would degrade this figure, raise the number of road accidents, the number of injured," he said. "We are proud to have shouldered our responsibilities. Before the end of the debate, after the debate, everyone will have to assume theirs before the French."
Philippe has stuck his neck out over the new speed limit, a source of tension with Macron, who reportedly blasted it as a "stupid mistake" of the prime minister's doing and not in his electoral manifesto.
The president has said he would be willing to find a more "intelligent way" of cutting deaths while aides have let it be known they could be willing to grant local authorities the power to rescind the speed limits in certain cases.
But Chantal Perrichon, president of the "league against road violence" said that allowing local MPs or regional heads to set speed limits would herald a "return to feudalism, with barons who had the power of life and death over serfs".
This article originally appeared on the Daily Telegraph.