National requirements governing translations of European patents
Any contracting state may make the protection conferred by a European patent granted (or amended or limited) in a language that is not one of its official languages contingent upon your filing a translation into one of its official languages or its prescribed official language. It may also require you to bear some or all of the cost of publishing the translation. The same applies to extension states.
For more details refer to "National law relating to the EPC" and to the key points of the London Agreement, to be found on the EPO website at www.epo.org.
You should take great care to comply with these requirements, especially those governing time limits for filing translations, so as not to undermine the protection conferred by the patent in the designated contracting states.