Harmonised monetary and fiscal policies is a feature of

Economic integration progresses through stages, each involving deeper cooperation between member countries:

1. Free trade area: Member countries remove tariffs and quotas on trade between themselves, but each country maintains its own external trade policy towards non-members.
2. Customs union: Members remove internal trade barriers and adopt a common external tariff against non-members.
3. Common market: In addition to a customs union, members allow free movement of factors of production (labour and capital) across borders.
4. Economic union: Beyond a common market, members harmonise their monetary and fiscal policies, creating coordinated economic governance. This may include a common currency, a central monetary authority, and aligned tax and spending policies.

The harmonisation of monetary and fiscal policies is therefore a distinguishing feature of an economic union, as it represents the deepest level of integration short of full political union. Neither a free trade area, a customs union, nor a common market requires member states to coordinate their monetary or fiscal policies.