Von Beckstein is a fictional German army soldier, a small character in the series Allo Allo. At some point the name was assumed by Roger LeClerc when he was disguised as a soldier wearing a German uniform.
It is suggested that Von Beckstein is either, a name made up or a "real" German soldier, but never seen on screen. The latter is supported in a interrogation by Denise Laroque of two assumed German soldiers with stolen uniforms (Rene Artois and Roger LeClerc) where LeClerc claims to be Von Beckstein. It is assumed that the uniform carried some sort of identification of Von Beckstein.