A rough translation reads like that:
You can see some on Yahoo News
In front of 20000 spectators on the Hamburg gangways, Tommy Haas and Roger Federer showed a spectatcular showmatch on a floating tennis court within festivities due to the Hamburg Harbour anniversary which was held to promote the Hamburg Tennis Masters.
Federer said: "That was a sensational activity and it was great fun for me to play with Tommy here in front of the Hamburg people on this ponton. We tried to get as close as possible to the crowd and it was terrific."
A tugging boat pulled Federer and Haas near the gangways where they were received by the enthusiastic crowd of the Hamburg harbour anniversary and where they showed for about 30 minutes that they belong to the best tennis pros on the world. After the match they said good bye by shooting some tennis balls into the crowd. Ball boys on rubber rafts fished the tennis balls which landed in the water.
Haas: "That was a real honour that we both could play in front of this great scenery. First we had to get used to the unknown surface, but later it felt like a real tennis court and we had good rallies."