To be certain, you should:
* Consult your owner's manual: This is the most reliable source of information. The manual will have a diagram showing the fuse box location and a fuse map.
* Check online forums: Search for "Peugeot 306 engine fuse box location [year of your car]" on forums like Peugeot forums or general car forums. You might find pictures or more precise descriptions.
Without knowing the specific year and model of your Peugeot 306, it's impossible to give a more precise location.