Because English is the language of the internet, and a good midpoint between Germanic and Romance, it will continue to serve as a standard European language. Additionally, the majority of Europeans aren’t native speakers of French or German. Additionally, wise Europeans remember what happened the last couple of times French and German competed for dominance on the Old Continent. English is the perfect EU language precisely because it belongs to nobody, and thus everybody. Not to mention that it will be very valuable for communication (political and commercial) between the EU and most other countries in the world. Most Europeans will still want to learn English, and then maybe a neighboring language, and then perhaps Mandarin if they have time.