Seals (French: cachets) and stamps (French: timbres) are often used in the Obscure World.
A seal was released with each album of La Frontière Invisible.
Seal of the Transport Virtual Urbanautiques Company. After an idea of the participants of the discussion forum “The Obscure Cities and Us” at BD Paradisio.
See also: Société des Transports Virtuels Urbanautiques (S.T.V.U.)
Seal “Light caused by the Cities”. There is a limited edition signed and sent to club members of the "Lumière sur les cités" club for the year 2000 AD.
Some other stamps used by Lumière sur les cités collected by Sylvain St-Pierre