Michel,

The book "Interzonenzüge", published by GeraMond Verlag (try them or AbeBooks and Amazon if out of print), is a very good general study of the whole subject, which started with the US, French and British military trains in 1945.

Searching here and on other forums will produce previous threads on interzonal and military services.

http://groups.yahoo.com/group/DutyTrain/ is a group site devoted to the military trains across the Inner German Border and I'm sure some French input would be welcomed there.

The TMFB ("Le train militaire français de Berlin", forgive my schoolboy French if it's not right), one of the earliest, was the last to run in 1994.

David