I saw one of the other questions asked, someone who who was trying to get through route 18. You said to go to Lysandre cafe and beat team flare. No body was there from team flare. What do info now?
If you have beaten the Anistar Gym, go to Lysandre Cafe and talk to the people there. They are disguised as Team Flare Grunts. The bookshelf in the back of the cafe leads to Team Flare's secret hideout.
Hope this helped!
Edit: Source: Experience