Note the German Foreign Office:
For the 24th and 25.11.2012 in Bangkok a large demonstration in the area around the parliament, the Dusit Zoo and the seat of government ("Government House") has been announced. The government has for the 22nd time to 30.11.2012 set for the Bangkok city districts Phra Nakorn, and Dusit Pomprab special statutory arrangements on internal security force. In these districts, it can therefore inter alia come barriers to access, limitations on the use of electronic devices and possibly curfews. Travelers are advised to avoid the area during this period. The other usual tourist areas, both in Bangkok and in the rest of the country are not affected.