Four cars were set alight in the early hours of Sunday morning in Chêne-Bourg in Geneva.
No one was hurt, but witnesses say there were a series of small explosions.
The Geneva fire service say they dispatched one engine at 03:41 Sunday morning, but decided to send more vehicles before the first one had arrived following more calls from the public.
A spokesman for the fire service says it shows how important it is to make the calls, even if you think someone else has already reported the fire.
The more eyes the better - says the spokesman.
In the end, five fire engines were sent.
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