European diplomacy operates across multiple layers:

• Macro-layer: the European Union and regional organizations (Council of Europe, NATO).
• Meso-layer: bilateral relations between EU member states and external partners.
• Micro-layer: city diplomacy through networks such as Eurocities, C40 Europe, and direct partnerships with cities worldwide.

Example: Paris and Berlin shaping climate diplomacy through C40, while Barcelona leads global conversations on digital rights.