In September 2017, fuel in Belgium averaged €1.334 for petrol

Petrol, monthly average€1.334/L
Diesel, monthly average€1.237/L
LPG, monthly average€0.514/L
Weekly bulletins held for September 20174

Monthly averages for Belgium across September 2017, from the stored EU Weekly Oil Bulletin monthly history (European Commission, CC BY 4.0).