There are plenty of agencies, but you need to know where you want to go. Finding employment as a foreigner is not easy, especially if you don’t speak the foreign language.
I live in Germany and work for artists/decorators is difficult to find and tax laws etc are scary. There is also 14 - 20% unemployment rate in our area, so the first thing an agency must answer to the government is why they are hiring a foreigner when a local can do the job just as well.
On a happier note, if finding decorating work does not work out, think about your other skills and go from there.