Everything your students need to know about ordering a coffee in France is in the first part of this document called "Comment commander un café en France". The second part of the document has a simple yet effective dialogue called "Dans un café" that will allow your students to practice ordering a coffee (and/or other café beverages) through repetition.
Have your students practice the dialogue by replacing the underlined words with the words from the list below the dialogue.
P.S. Your feedback would be greatly appreciated.