For location, you basically need him to get lucky. He happens to arrive somewhere that has a world-famous landmark that existed 2,500 years ago. In France, that probably means either the White Cliffs of Dover or the Lascaux cave (which was buried in recent history until 1940, but might have been more accessible 2,500 years ago) (I hope he has a torch/flashlight on his keychain).
Edited to add: There are also the megalithic complexes at Carnac in Brittany, but unless he’s sufficiently expert to recognise a much younger version of them, that just tells him that he’s somewhere in Britain, Ireland or Brittany. A Canadian layman would probably think “Stonehenge” and be wrong.
If he can arrive further south and knows a bit of history, Marseille exists in 500BC and is a Greek city called Massilia, which name he can probably get from the locals with mime and sign language.