I was staring at that too, I think it must be a sticky bedbug trap in some containing tube

I don't know how large a one euro coin is, but even assuming it's as tiny as the tiniest coins we have here (15mm in diameter), those bedbugs are still terrifyingly huge! Now, having looked up how large a 1€ coin is (23.25mm), and estimating from the image, those bedbugs are around 5mm long!

... I thought they're huge, but having looked things up, it's right about average. I thought they're usually much smaller than that over here though (roughly 1mm in length). I probably have had the good luck of never having seen a bedbug in my life. Cockroaches though, are a normal part of life around here, hehe.