Different from Germany and Britain, the designated French PCT application cannot directly enter France, because when the PCT protocol was adopted in France, France introduced the 45 (a) clause of the PCT protocol, which "closed" the channel directly entering the French national phase. Therefore, the only way for PCT to apply for patent protection in France is for PCT to apply for a European patent (Euro-PCT) from the European Bureau, and then it will take effect in France, thus obtaining patent protection in France.