WARNING
Gasoline is highly flammable and poisonous.
It burns violently and can cause serious personal injury.
Never allow sparks, flames or smoking materials near gasoline.
Turn off the engine before refueling.
Whenever you are around gasoline, avoid inhaling fumes and any skin or clothing contact.
Direct skin contact with fuels and the inhalation of fuel vapors are damaging to your health.

WARNING
Overfilling of the fuel tank may create pressure in the system which could cause a gas discharge. This could cause the gasoline to spray back out when removing the fuel pump nozzle, which could cause personal injury.

WARNING
C 300 and C 300 Sport with automatic transmission:
Flexible fuel vehicle (with Ethanol up to E85! sticker on the fuel filler flap):
Ethanol fuel (E85) and its vapors are highly flammable, poisonous and fast burning.
Ethanol fuel can cause serious injury if ignited, or if you come into contact with it or inhale its vapors. Avoid inhaling ethanol vapors. Avoid skin contact with ethanol. Extinguish any naked flames before refueling. Never allow sparks or smoking materials near ethanol.

Do not use diesel to refuel vehicles with a gasoline engine. Even small amounts of the wrong fuel result in damage to the fuel system and engine.

Do not switch on the ignition if you accidentally refuel with the wrong fuel.

Otherwise, the fuel will enter the fuel lines.
Notify a qualified specialist workshop and have the fuel tank and fuel lines drained completely.