It's a shame: the "Walibi Schtroumpfs" does not exist as such anymore: The park is still there, but it is no longer associated with the Smurfs.
It's called "Walibi Park Lorraine" and that's it. (Lorraine is the name of the county where it is)
I actually made a point of going and checking out when I was coming back from Strasbourg a couple of years back: Not a Smurf in sight!
Xavier had some picture on his web site of what it was like before, and I believe he also explains when and why the park is no longer a Schtroumpf park...
Here is a pic of what the entrance look like now...