Customs triangulation is a trade operation involving three parties in different countries: a seller (A), an intermediary/reseller (B) and an end buyer (C). Goods are shipped directly from A to C, but invoicing follows the path A → B → C. This is very common in international trade and has specific customs and tax implications. Main types: 1) EU intra-Community triangulation — all three parties in different EU countries: goods circulate freely but require correct Intrastat registrations and VAT numbers; 2) Third-country triangulation — one party is outside the EU (e.g. Switzerland): goods cross a customs border requiring import/export declarations, EUR.1 or invoice declaration, and correct identification of seller and consignee in customs documents; 3) Triangulation with processing — goods are sent to a third country for processing before delivery: inward or outward processing regimes apply. Critical aspects: commercial invoices must clearly state Incoterms for both A–B and B–C legs; transport documents (CMR, B/L, AWB) show the physical route (A to C), not the commercial path; preferential origin is determined by place of production, not the intermediary's location; VAT must be managed carefully to avoid double taxation — in the EU, the exemption for intra-Community supplies (Art. 138 VAT Directive) applies; in Switzerland, intermediary B does not necessarily need a Swiss VAT number if goods do not enter Swiss customs territory. A common error is incorrect customs declaration: sender, consignee and declarant must be accurately stated to avoid customs valuation disputes. Franzosini handles triangulation operations between Switzerland, the EU and third countries daily, ensuring correct documentary, customs and tax management throughout.