Curiously, the countries where Catalan language is official are Spain and Andorra. Particularly, in Spain Catalan is spoken in Catalonia, Valencia and in the Balearic Islands.
In Andorra, a small country in the heart of the Pyrenees, Catalan is the only official language although Spanish and French are widely spoken. In Italy, the small city of l'Alguer in the island of Sardinia but it is not an official language in Italy.

Nice answer Toni, thanks.
By the way, I have been doing some research and found out that although Catalan is spoken in France, particularly in the Roussillon and the Pyrénées-Orientales, it is not recognized officially because the French Constitution of 1958 considers French as the only official language of the country.
They are lucky in Spain that two languages can be recognized as official!
As a curiosity I will add that Catalan is also spoken outside the Catalan Region: in Aragon (Area of La Franja) and in Murcia (Area of El Carche).