After struggling to find a car park, roofer Louis Cole, 27, left his Ford Transit outside a church early on a Sunday and went off sightseeing.
But nervous locals arriving for mass in Paris called police who searched the van and found a passport, which made them suspect an IS plot.
Bomb experts carried out a controlled explosion, creating a huge hole in the roof and blowing out the windows.
The wreckage was then towed away. Louis, 27, from Faversham, Kent, said that he and Alex Hogben, a carer, “drove to Paris on the Friday and the car parks were all so expensive as the van is quite tall.
“We found the spot outside the church and parked up there thinking it would be all right.
“When we came back, the van was gone, and we believed it had been towed away.
“When we arrived at the compound to pick it up, we were told what had happened and couldn’t believe it.”
Louis, who owns his own roofing business, is still awaiting payment for the damage which left the van a write-off and is demanding an apology for the May bank holiday incident.
French police are on a state of high alert following a number of terror attacks across the country.
In the latest, on April 20, policeman Xavier Jugele, 37, was shot dead by a gunman armed with a Kalashnikov who opened fire at traffic lights in the busy tourist spot in the heart of the capital.
Jugele was the fifth policeman killed by jihadists in attacks that have claimed more than 230 lives across France since January 2015.