Paris is a great city - loved it! They have a great "cafe" culture, it just doesnt include quality coffee - they have a lot to learn about espresso.
If she drinks espressos, tell her to ask for "ristretto" espressos - petite! (Hopefully she wont get too many blank looks.)
Best espressos we had recently in a 4-day stay in Paris were in the cafe at Musee dOrsay and in an historic old cafe in Bvd St Germain called Cafe de Flores.