The businessman, 58, was driving his £164,000 car at 25mph in a 40mph village zone when off-duty Assistant Chief Constable Nick Croft saw him.
After a roadside check on the car’s ownership and the ticking off Denis, of Southerndown, South Wales, was allowed to go.
He said: "I was flabbergasted when he said I wasn’t going fast enough. The road is badly lit, with a nasty bend, and often has sheep on it. I felt 25 was safe."
Locals in Ogmore-by-Sea want the 40mph limit lowered.
A police spokeswoman defended Mr Croft, who lives nearby.
She said: "The Assistant Chief Constable was following the Ferrari, which was going very slowly, and he thought, ‘What if it was stolen?’"