Tim,

Here's some Frenchy style marks...

They look relatively similar to British style marks (I think) until you get to 6,7,8, and 9.
I'm no expert on French framing styles, but I believe that all interior secondary framing pieces (braces, girts, etc.) would be centered. There would be a level mark on every piece, and posts would need some kind of 2' mark (because they are in 2 scribing assemblies), but I don't know where they traditionally fall on the post. There would be no English tying joints or jowled posts. The French also mark their cuts differently using 'x's to mark where not to cut, and 'o's to mark the waste. Maybe some of the Timber Tour de France tourists, or Mo could add something to this.

and Carlos,
I basically never snap lines on square rule (in contrast to Will), as long as the reference edge is straight. And I could be wrong here, but there are no centered mortises in traditional square rule. Cutting a fully housed mortise on a non-reference face on an out of square timber is pretty damn hard. You could make a router jig referenced off the reference face, use a whole bunch of squares to check everything, find a square timber, or just scribe the braces.