The measure applies to single-lane roads without central reservations, and affects 400,000km of road.
Prime Minister Edouard Philippe introduced the measure in January as part of 18 government proposals designed to make roads safer and reduce road traffic accident deaths across France, prompting opposition and protests ever since.
Mr Philippe has said that two-thirds of serious road accidents happen on the roads in question, and has estimated that up to 400 lives could be saved every year due to the change.
Yet, opposition groups have contested the claim, saying that the change will make no difference, and instead lead to congestion, frustration, isolation, and excess bureaucracy in enforcing it.
A recent poll found that almost two thirds (74%) of French people were against the change, with many seeing it as an attack on their personal freedom. Some areas, including the Creuse department, have publicly said they will not be installing new speed limit signs, in protest at the move.
A statement this week from official Prime Minister’s residence, Matignon, read: “The Prime Minister is not ignoring the reactions to this measure, but reminds people that it is about preserving human life, and avoiding tragedy.”
As well as controversy over the move’s disputed effectiveness, Mr Philippe himself has received criticism for his personal support of the measure, which was not mentioned in Mr Macron’s presidential campaign.
Similarly, the move has not received universal support in the government - including most notably from interior minister Gérard Collomb, who has avoided making a statement one way or another.
The Prime Minister has also been criticised for taking a “top down” approach from Paris, and applying heavy handed rule in rural areas.
The Matignon statement defended this, saying: “Since 2013, the number of deaths and severe injuries on the road was rising, despite it having previously been dropping for decades. The Prime Minister has stepped in to take effective measures and save lives.
“The fact that the subject was not a key part of the campaign does not give us an excuse not to act.”
François Patriat, a senator close to President Macron, has added his voice to the controversy, saying: “I remember the days when mandatory seat belts were introduced, when [speed] radar was brought in...even if they are unpopular, these brave measures always pay off in the end."
This Friday (June 29), Mr Philippe again stated: “To say this in a straightforward way, my objective isn’t to annoy everyone. The objective is to reduce the numbers of deaths and serious injuries.”
The measure is now expected to be “on trial” for the next two years, to see if it makes any difference, with President Emmanuel Macron saying that if no change was recorded, “we will stop and give control back to the departments”.
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