The group is set to play this Saturday in the hall which has a capacity of 10,000.
Braving the heat by day and cold by night, the fans aged 13 to 22 have been camping out in some 15 tents on concrete in front of the Arena, a hall located between the airport and a Geneva highway.
Some of these teenagers from Switzerland and France had arrived as early as last Saturday.
The concert organizers have had to hire a security guard to keep watch over the girls at night.
Tokio Hotel released their first album “Schrei” (Scream) in May 2006 and sold some 600,000 copies in six days in Germany. It also quickly became a major success in France, Austria and Switzerland.