nationalism is a strong feeling of pride in and devotion of pride to one’s country.
It created tension between France and Germany.
During Germany's unification of 1871 Germany occupied territories from France.
France wanted to regain its lost provinces Alsace and Lorraine following her defeat at the Battle of Sedan in the Franco-Prussian war of 1870-71. Nationalism in the Balkan also served as a source of tension.