Rule 35⁵⁴
General provisions

(1) European patent applications may be filed in writing with the European Patent Office in Munich, The Hague or Berlin, or the authorities referred to in Article 75, paragraph 1(b).

(2) The authority with which the European patent application is filed shall mark the documents making up the application with the date of their receipt, and issue without delay a receipt to the applicant including at least the application number and the nature, number and date of receipt of the documents. 

(3) If the European patent application is filed with an authority referred to in Article 75, paragraph 1(b), such authority shall without delay inform the European Patent Office of the receipt of the application, and, in particular, of the nature and date of receipt of the documents, the application number and any priority date claimed.

(4) Upon receipt of a European patent application forwarded by the central industrial property office of a Contracting State, the European Patent Office shall inform the applicant accordingly, indicating the date of its receipt.