I know this does not answer your question about the French Dressing but this seemed like a good place to let you know about a dressing I use at work.

I keep a bottle of Newmans' Own Olive Oil and Vinegar in my drawer at work. It does not require refridgeration after opening so it is perfect for the office space

No idea about French though. You could always mix a Ranch dressing with a little vinegarette to make your own french. Might be worth trying to come up with your own unique taste

Cody