Well, at least Lyon :-) Normally, 8 december is the Festival of Light... to thank the Virgin for saving Lyon from the plague some time in the 15th century, while neglecting to save most of her competitors in the silk industry. Traditionally, this involved people putting candles in their windows on the night of the 8th... but over the last 20 years it has blown out into a massive 4-5 night son-et-lumière, with 4 million people packed into the city (usual population 1 million...). A couple of years back I spent an hour trying to walk across a 4 lane bridge towards the city centre, the crush of bodies was so dense. I gave up, you needed to arrive mid afternoon.
This gives some idea pf what goes on at one of the major sites... but it's the whole city, and of course no access control at all.
https://www.youtube.com/watch?v=cG9IE_4kFVAIt doesn't take much imagination to think what a few nut cases with guns and suicide vests could do ... :-(
So for this year it has been cancelled, but there were enough remnants already installed that the locals came out for a look
