The authorities raked in 15.3 billion euros in undeclared tax in 2014 and supplemented that income with four billion euros in fines, ministers announced on Tuesday.
The total was 1.3 billion euros more than in 2014 and higher than any previous year.
The government is claiming the credit for its anti-tax-dodging drive, which has received extra resources even if it is still reported to be swamped with work.
But it has undoubtedly been helped by a whistleblower who revealed that the Swiss arm of the British HSBC bank helped clients - many of them French - hide billions of euros and by the Luxleaks revelations of major international tax fraud.
In fact, France has collected 1.9 billion euros in penalties for holding secret foreign bank accounts and 40,000 people have come forward to admit to hiding money abroad.
Tax officials hope to net 2.7 billion euros from this source in 2015 and they're well on their way, with 1.6 billion euros already collected.
The amount collected from benefit fraud has also risen - by 34 per cent - although the sums collected are a lot lower.
Some 427 million euros were collected in unpaid social security contributions for undeclared workers, while fraudulent benefit claims were worth 424.96 million euros.
Customs officers would also like their share of the credit.
They collected 356.9 million euros - up 10.5 per cent in a year - largely due to a haul of 422 tonnes of contraband tobacco.