France, Oct. 27 -- Twenty years on, the deaths of French teenagers Zyed Benna, 17, and Bouna Traore, 15, still weigh heavily in Clichy-sous-Bois, the Paris suburb where they were electrocuted while fleeing a police identity check. That tragedy spurred 21 nights of unrest across France.

It was 5.30pm and night was falling as a group of 10 boys headed home after a day at the football pitch. A resident saw them near a building site and called police, wrongly fearing a break-in.

Fourteen officers arrived and began chasing them. On one side was a simple suspicion of an offence. On the other was a deep fear of identity checks.

Three boys climbed the fence of an EDF electrical substation as they ran. Two officers nearby saw them. One said ove...