Don't know of any free-fighting as such but when I was there last I saw a group called ''Liu He Men Kung Fu'', as it was the Chinese new year and they were everywhere in Chinatown following the Dragon and firecrackers around the streets in celebration. (check out the pic I took). It's Kung-Fu but not Jiu-jitsu, they maybe able to point you in the right direction if Google fails you. Their web is http://www.liuhemen.org/items/3-1/
Thanks fedor, Ive been to their site but its all in dutch, do you know where it is located more or less? Thanks