"Tu peux chercher ça sur Internet."
Translation:You can look for that on the Internet.
Not insane. The usage is simply different. In English, "look for that on Internet" does not make sense to me. You would say "...on the internet". Sometimes you would just say "online."
In French, you would simply say "sur Internet." Some people say "sur l'internet" is also possible, but it is less common, and it sounds weird.
- English: on the Internet
- French: sur Internet