Gratuity uses from Bascharage & Boevange-sur-Attert

Revenue stamps are sometimes used to indicate the waiver of a tax – what I call “gratuity” revenues.  Here are a couple examples:

2-Franc Tax Waived (“gratuit”)
Bascharage
9 Nov 1939

6.40-Franc Tax Waived (“Sans Taxe”)
Boevange-Sur-Attert
19 Apr 1963