'Picon' is an alcoholic (18%), aromatic mixer used in 'Picon Vin Blanc' and 'Picon Bière'.
'Picon Vin blanc' is normally drunk as an aperitief and its exact make up often varies from cafe to cafe.
The further you go away from France Flanders, the more likely it is that the citron or finishing spirit will be missing.
'Picon Bière' is a small glass of blond or brown beer with first a centimeter or so of Picon poured into the bottom of the glass. This can be quite a refreshing summer drink, or a dangerous hangover cure!