Try the following:
$setmulti(genre,Loveparade; %genre%)
Note the semicolon followed by a space!
Also one idea to improve the handling: In Options > Scripting add this script as a separate script, give it some descriptive name, e.g. “Set Loveparade genre”. Now make sure this script is inactive (the checkbox is not active).
Now you can apply this script manually to any selected files or albums by right clicking and selecting Run script… > Set Loveparade genre in the context menu. This makes it easier to apply this to any files you want without changing anything in options.