Macron faces most serious test as fuel protests threaten French gridlock

(CNN)Emmanuel Macron is braced for one of the toughest tests of his 18-month presidency on Saturday with planned protests over rising fuel taxes set to bring France's roads to a halt.

Opposition has mounted to France's spiraling fuel costs, which has seen diesel prices surge 16% this year from an average €1.24 ($1.41) per liter to €1.48 ($1.69), and even hitting €1.53 in October, according to UFIP, France's oil industry federation.

A grassroots movement -- dubbed the "gilets jaunes" or "yellow vests" in reference to the hi-vis safety vests worn by drivers -- has galvanized motorists up and down the country, who are now threatening to cause blockages on arterial road networks.

Agence France-Press reports that 700 blockages are planned for Saturday, while website www.blocage17novembre.com states that protests are planned in all 95 of France's mainland departments.

A petition on Change.org has also received more than 850,000 signatures, calling on the French government to lower the cost of fuel.

The price hike is in large caused by a leap in the wholesale price of oil, with Brent Crude oil -- a benchmark for worldwide oil purchases -- increasing by more than 20% in the first half of 2018 from around $60 a barrel to a peak of $86.07 in early October.

French protesters are however not directing their anger at Opec for reducing oil production, or at the US administration for implementing tariffs on Iran, crippling its oil exports.

Macron is instead bearing the brunt of widespread French chagrin, with many protesters furious at the current leader's extension of hostile environmental policies implemented under François Hollande's government.

Notably, taxes were increased by 8 centimes last January on diesel, and by 4 centimes on petrol. Tax on diesel will also increase by another 6.4 centimes in 2019, and by 2.9 centimes for petrol. These rises follow many decades of under-taxation of diesel in France.