It has been billed as the first austerity plan since Nicolas Sarkozy reined in public spending 13 years ago and on a par with Socialist President François Mitterrand’s famous cost-cutting “U-turn” in 1983 after a ruinous tax-and-spend drive.

“This is the most violent austerity plan that this country has ever seen,” said Manuel Bompard, MP for the hard-Left LFI party. “It will cause French people to suffer,” he added. Jean-Luc Mélénchon, the party’s figurehead, called it “calamitous”.

However, experts at France’s High Council of Public Finance, which answers to the state auditor, suggest Mr Barnier’s supposedly fierce spending reductions were not what they seemed.

According to its analysis, a €42bn “structural effort” is required to hit the 5 per cent deficit target. However, it calculated that of this total, 70 per cent are set to come from increasing taxes, and only 30 per cent from spending cuts – the reverse of what Mr Barnier has claimed.

While the tax hikes appeared clearly set out, it warned that the cuts were “not all documented” and their implementation will be “difficult”.

Hikes include exceptional taxes on large companies (€8.5bn) and individuals with very high incomes (€2bn), a six-month freeze on pensions paid to retirees, a tax on share buybacks and a tougher tax on polluting cars. There will also be new taxes on plane tickets and private jet usage.

France’s overall rate of taxes and social security contributions, which are already the highest in Europe, is set to rise even further to 43.6 per cent of GDP by 2025.

Cuts include reduced reimbursement for medical costs and sick pay. In education, 4,000 teacher jobs are set to be cut next year. Overall, the government is planning to cut a net 2,200 public jobs in 2025.