A primate city is the largest city in its country or region, disproportionately larger than any others in the urban hierarchy
List all of the primate cities in Europe.
A primate city is a major city that works as the financial, political, and population center of a country and is not rivaled in any of these aspects by any other city in that country. Normally, a primate city must be at least twice as populous as the second largest city in the country. The presence of a primate city in a country usually indicates an imbalance in development (Wikipedia)
For example, Bangkok is a Primate city
Vatican is excluded as there are no real cities in the state.