Can I use the priority of my national patent application when filing a European application?
Yes. If you or your predecessor in title have filed an application for either a patent or the registration of a utility model or a utility certificate in or for any state party to the Paris Convention for the Protection of Industrial Property or any member of the World Trade Organization, you may claim priority when filing a European patent application in respect of the same invention. You must do so within 12 months of the date of filing of the first application.
If the previous application was filed in an EPC contracting state, you can also designate that state in the European application. The previous application whose priority you claim may also be a European or international (PCT) application.
For further details see the European Patent Guide, point 4.1.017 ff.