Europe

In Europe, workers in the service industries are generally paid higher wages than in America, and therefore tipping is not always customary. When people do tip they generally tip less than in the states. However, it varies from country to country. Central European countries like Germany, Switzerland, Austria, and Holland tip between 5-10% as a common practice, although it is not always required to tip. Countries like Spain and Italy are not advocates of tipping. In France and the Scandinavian countries, a service charge is included in the bill, while Ireland and the U.K. generally adhere to an optional tipping policy. When traveling in Europe, unless you are in Spain or Italy, it is generally a good idea to leave a tip close to 10% unless the charge is included, or the service was not satisfactory.
source: gocurrency