that's a re-usable hiking/biking/outdoor bottle.
The black top of it has a loop for carabiners.
https://www.dailystar.co.uk/news/world-news/781180/lyon-explosion-injuries-victor-hugo-golden-brioche-police
Terror fears as nail bomb explosion injures 13 in Lyon
Conveniently… he was simply a man wearing a mask… In other news, pic related.