Bootlight with a microswitch

I found some info about light in the boot on the German Peugeot Freunde Forum, see this topic. This guy mounted a microswitch into the original rear doorlock.
He also mounted an original boot light from a Peugeot 206 in his boot.

I also have a light in the boot but I have to switch it on manually.
So I'm thinking about a switch myself and I like this modification very much.