There are two songs featured in this episode. They are "Nonchalant" by Chapeaumelon and "Ça plane pour moi" by Plastic Bertrand. They're both in French.
Velma said that Fred paid francs to use the telescope but, since 2002, they MUST be euros (€), Europe's Single Common Currency.
Before going into the sewer, Daphne and Velma put on Daphne's special "wallowing galloshes". Yet when they get flushed out of the sewer, Daphne and Velma are wearing their usual footwear instead.
Danica LeBlake: The gargoyle would've gone away. But then Daphne showed up with her meddling amis, and Guy and I had lead you off my track.
Fred: I can look through this telescope with these little quarter thingies.
Velma: They're francs.
Fred: I thought they were mine.
In this episode, the van's lettering reads Le Machine Mystere (The Mystery Machine in French).
When they're trying to rescue Shaggy and Scooby we can hear the song "Nonchalant" by Chapeaumelon.
Culprit: Danicaa LeBlake!
Reason: Wanted to get out of modeling and have a quiet life like Daphne. LOL!
The music played during the chase scene is "Ca Plane pour moi" by Plastic Bertrand.