Is it possible to object to a particular application, either before or after it has been granted?

Yes, in two ways:

1. In proceedings before the European Patent Office, following publication of a European patent application, any person may submit observations concerning the patentability of the invention to which that application or the granted patent relates. These observations must be filed in writing in English, French or German and must include a statement of the grounds on which they are based. There are no fees for presenting such observations. We advise using the official EPO web-based filing form, which has been designed to help you to formulate your observations in a structured and concise manner. It is available free of charge from the EPO website. Filing observations does not make you a party to any official proceedings the EPO undertakes, and you will not be informed by the EPO about the further outcome of the patent grant proceedings. However, it is important to note that submissions filed as third-party observations will be placed in the public part of the file of the patent application or patent and will thus be accessible to the public. The observations are communicated to the patent applicant/proprietor, who may comment on them.

   For further details see:

   • Notice from the European Patent Office dated 5 July 2017 concerning the filing of third-party observations under Article 115 EPC (OJ EPO 2017, A86)
   • Third-party observations form
   • Printable notes for users of the third-party observations form
      
2. Up to nine months after publication of the mention that a European patent has been granted, any person (with the exception of the patent proprietor themselves) may file notice of opposition to the patent with the EPO. The notice of opposition must be filed in a written reasoned statement. That means that the opponent must state at least one ground for opposition under Article 100 EPC and indicate the facts, evidence and arguments presented in support of the ground(s). Otherwise the notice of opposition will be rejected as inadmissible.
   
   We advise using the official EPO opposition form (2300), which can be filed using Online Filing (OLF) or Online Filing 2.0, or can be downloaded free of charge from the EPO website. Notice of opposition is not deemed to have been filed until the opposition fee of EUR 880 has been paid.
   
   For further details of the opposition procedure see the European Patent Guide, point 5.5 ff.
   • Oppositions
   • Forms
   • Article 100 EPC: Grounds for opposition
   • European Patent Guide