In March 2018, fuel in Belgium averaged €1.327 for petrol

Petrol, monthly average€1.327/L
Diesel, monthly average€1.319/L
LPG, monthly average€0.494/L
Weekly bulletins held for March 20184

Monthly averages for Belgium across March 2018, from the stored EU Weekly Oil Bulletin monthly history (European Commission, CC BY 4.0).