I think Clichy canes are very distinctive, personally, but St Mandé and Grenelle are a different matter. A French collector - Philippe Frère - has carried out a lot of research on the two factories ( I think he was the man who helped confirm the existence of these factories together with Patty Mowatt and others). He has written several articles about them, including one in the PCA Bulletin 2012 which has over 40 pictures of Grenelle weights and another 17 of their canes. I think that 11 cog canes are distinctive of Grenelle, as are canes with multiple layers of colour (such as those in the outer row of the Grenelle weight I have shown above). But not all of their weights have these features, of course - one is then looking at the style of the canes.