The murder victim, a 43-year old civil servant for the tax authorities, was found dead on Monday, killed “most likely by repeated stabbing”, the prosecutors’ office in the northern French city of Arras said.
The suspected killer, a 46-year-old antiquities dealer, was then believed to have killed himself with a firearm, it said.
The suspect, described by the local mayor as “an ordinary guy”, locked up the tax inspector and a female colleague during a tax audit of his business, it said.
“The republic is weeping for one of its own,” Budget Minister Gabriel Attal said.
He said it was “revolting” that a public servant was killed “because he did his job”.
The inspector arrived Monday afternoon at the antique dealer’s home, accompanied by a colleague, to check his accounts.
Attal said usually agents were sent on tax check missions on their own, but this time there was backup because there had been tensions during previous visits to the antique dealer’s business.
Prosecutors said the businessman tied them up and stabbed the inspector, leaving the colleague “terribly shocked” but otherwise unharmed, the prosecutors’ office said.
A union for tax officials said the case showed that its members had a “potentially dangerous” job.
The dealer, a divorced father of two, moved four years ago to the hamlet of Bullecourt, its mayor Eric Bianchin told AFP.
He bought a farm from where he sold bric-a-brac which he picked up at auctions and yard sales around the area.