Just spent 3 nights in Paris. I naively thought (I'm fairly new to GF) I could eat out providing I stuck to plain things like grilled fish and steaks. Not so. I came back more ill than I've been in a long time. We're not giving up on Paris - we love it - but cosy bistros are out from now on unfortunately. In future we'll rent an apartment and have meals in. Then hit the cafes for a glass or two.
A website I stumbled on all too late is very useful and informative on GF Paris, is
And one baker I can recommend from first hand experience is this one. Good for lunch or takeaway.
They do very nice focaccia style breads, and have terrific sandwiches and cakes etc. Open Tuesday to Saturday daytime and half day Sunday.