European Union–Mercosur relations
Relations between the European Union and Mercosur were established soon after the entry into force of the latter bloc. Being both the European Union (EU) and the Southern Common Market (Mercosur) custom unions, their relation has been however described as "asymmetrical", both in terms of their contrasting stage of economic development and degree of institutionalization.
Source: Wikipedia — European Union–Mercosur relations (CC BY-SA 4.0)