The launch times for the World of Warcraft: Legion expansion have been posted on the community site for North America, Latin America and Australia/New Zealand. North America will see Legion go live at 12:00 am Pacific / 3:00 am Eastern on Tuesday, August 30th.
In Latin America, Legion will go live at 4:00 BRT and in Australia / New Zealand at 5:00 pm AET. From this release schedule, it may be inferred that Legion will launch at 12:00 am CEST.
In addition, the WoW team announced that, while the next PvP season won't begin until September 20th, players will begin earning Honor immediately on Legion's launch.
Read more on the World of Warcraft community site.