I have found four sentences in the French grammar book I have just read that all show different combinations of de after après and avant.
- Nous partons tout de suite après le cours
- Elle se brosse les dents après manger
- Nous dinons avant de regarder le film
- C'est un petit plat à manger avant le diner
What are the rules around de and le with avant and apres...my guess is the following
Before an infinitive, de is shown after avant but is not shown after après. Before a noun, no de is ever shown
Is there a reason why de is shown after avant but not after après?