Petroleum products are one of Luxembourg's specifically regulated price categories. Official maximum prices can change, so a road-trip budget should use the current government table rather than an old claim that fuel is always cheap.
Read the board like a dated notice
Maximum does not mean mandatory
The government framework sets a maximum price for regulated petroleum products. A retailer can charge less, so a small local comparison still makes sense; it just happens beneath a national ceiling.
Match the exact product name
Petrol grades, standard diesel and premium products can sit on different lines. Confirm the vehicle's required fuel before comparing numbers, especially with a rental car whose filler label uses another language.
The date matters more than the travel blog
Official prices are updated when the applicable ceiling changes. A bargain quoted in an article, forum or video can be out of date before your trip begins. Use the effective date on the current notice.
Do not spend the saving on a detour
A special drive to fill the tank adds distance, time and sometimes congestion. Compare the realistic litres needed with the extra kilometres before treating the border as a guaranteed saving.
The normal tank crosses more easily than spare fuel
EU traveller rules treat fuel in a vehicle's normal tank differently from extra containers. Luxembourg's traveller guidance limits the additional portable fuel allowance, so avoid turning a station stop into a customs problem.