The European Union (EU) is the world’s largest trading unit known as a customs union. There are currently fifteen member countries. In a customs union, internal tariffs are eliminated and the member countries form a single customs territory with a common external tariff. For example, once the good enters France or any EU member country and the common tariff is paid the good is free to circulate within all the EU countries. This is the freedom to move goods from country to country. This trade arrangement requires a lot of coordination from EU member countries. Since there is only one common external tariff, every country has to agree on what that tariff will be. This is not an easy process, and the application of trade solutions such as anti-dumping and countervailing duties have to be coordinated.

欧洲同盟（欧盟）就是关税同盟，是世界上最大的贸易单位。目前它有15个成员国。关税同盟中，其内部关税免除，成员国建立一个对于共同的外来关税的单一的海关边界。例如，货物一旦进入法国或其他欧盟成员国，交纳一次统一的关税，而在所有欧盟国家中自由流通。这是国家与国家之间货物流通的特权。这种贸易协定要求欧盟成员国之间进行许多的合作。由于只有一个共同对外关税，每个国家必须在关税上达成统一。这个过程并不容易，而且像反倾销和补偿关税这种贸易方案的运用也要调整。