Good on you for realising - just don't give in and plant your seedlings to see what happens. We had the wretched stuff (Russian, not French) growing up through the floor on the inside of the house from a patch outside.

bahhh. My totally organic ethos had to go on holiday as I had to nuke it with glyphostae for THREE years before I finally killed it (I think.....still keeping a watch on the living room floor.........), of course could kill the outside bit but couldn't nuke the bit growing under the house!

LCG