No there are no such companies in Greece. At some point in the past PEFC attempted an agreement with the Forest Service at the Ministry level, but to my knowledge this it was not finally advanced.
In Greece I do not know, but in case it can be useful for you, the Global FSC Certificate Database contains the most up-to-date information on FSC certificates, both Forest Management and Chain of Custody. The database can be used to verify that a company is FSC certified and search for FSC certified companies or products.