Infanta Sofía, the younger daughter of Spain's King Felipe VI and Queen Letizia, is changing her address - after a first year in Lisbon, she continues her second in Paris. She studies political science and international relations through a college linked to the University of London, with a plan to finish her studies in Berlin. The classes are in English, supplemented by Portuguese, French and German. Three cities, three languages, one diplomatic biography in the making.

Her new home is at the International University Campus in Paris, described as the largest residence for students and researchers in the region. The rooms are small - between 13 and 17 square meters - but the campus offers everything else in abundance: over 50 sports disciplines, a pool, tennis courts, a theater, a concert hall, a library, and even an ecological garden. Student life packed like a small town.

The interesting part is the one rarely mentioned when it comes to royal children - the bill. The residence costs between 820 and 1,200 euros a month, on top of which come around 300 euros for food, 40 for transport, and a bit for phone and entertainment. The reality of a European student, at least on paper - with the difference that behind the infanta stands a state budget, not a student loan.

Sofía is of age and increasingly taking on her institutional role alongside her studies. While her sister, crown princess Leonor, builds the military and ceremonial path, Sofía quietly gathers something harder to measure - an international education, languages and contacts across Europe. Once they come home, the question won't be who carries the bigger title, but who better understands the world in which Spain wants to play.