1. Only facts substantially relevant to the outcome of the litigation are the subject matter of evidence. The court takes into account ex officio well known facts and general teachings of common knowledge. Each party to the action bears the onus of proving the facts which are necessary to support his claim or counterclaim. Where the law provides for a presumption which supports the existence of a fact, such a presumption is in principle rebuttable.
CCP deals with eight means of proof: confession, direct proof, expert evidence, documents, examination of parties, witnesses, party oath and judicial presumptions. Witness testimony and documentary evidence are the most common means of evidence.
At the first hearing, both parties must present to the court all the evidence supporting their case, so that the hearing and all the evidence is completed at this stage. Only in exceptional circumstances will the court issue a judicial direction ordering that the evidence be further supplemented by the parties.
2. As a general rule a witness testimony is not allowed (a) against the contents of a document nor (b) to prove the existence of contracts or collective acts should the value of the subject matter exceed 5.900 Euros. There are, however, certain exceptions to this rule, in commercial transactions among others. Currently there is no limit regarding the number of witnesses a litigant is allowed to summon. The relevant litigant has to summon his /her witnesses at least three days before the date which has been fixed for their testimony and he /she must notify his /her opponent 24 hours prior to that fixed date. There are further restrictions as to the admissibility of witness testimony by certain persons, e.g. lawyers with regard to their professional secrets.
3. Documents are divided into two categories: public and private. The former category covers those documents which have been lawfully drawn by a public servant or official, such as a notary public; those documents bring about conclusive evidence erga omnes with regard to the facts recorded therein, provided that the public servant or official as above acted within his own competence. Public documents are considered authentic by presumption and may be challenged only for falsification. Foreign public documents are assimilated to Greek public documents from the view point of evidential power Greece has ratified the Hague Convention of October 5, 1961 on the recognition of foreign public documents.
The authenticity of private documents, if contested, has to be proven by the party who invokes and presents them. In principle, the facts recorded in those documents constitute proof only against the person(s) who signed them; however, where a private document is presented and invoked by the opponent or it is one of those considered to be a commercial or professional book, that document constitutes proof in favour of the litigant who has signed it. The evidential power of commercial and professional books, which are regarded as private documents, is subject to special rules. Private documents may also be challenged as false. The parties must present to the court the documents in their possession which "can be used for evidence", unless there is an important reason not to do so. This is particularly the case where the refusal for the granting of a testimony by a witness would be permitted with regard to the fact in question to be proven. The above obligation has however to be viewed under the evidential onus of the parties wishing to support their claim or counterclaim and the court's initiative on the conducting of evidence. Lastly, presentation of a document by a litigant may be requested by the other party to the litigation by means of a petition to the court.
4. With regard to expert evidence, the rule is that courts may order this where issues requiring special technical knowledge arise during litigation. Should the required level of knowledge be considered "highly specialised" and a party requests expert evidence, the court must order it. In practice courts often order expert evidence, even where it would not be compulsory according to law. The court may instruct the experts appointed in regard to the way they have to proceed with their report and also determines the time for the submission by the experts of their written report (which is adjudicated freely by the court who ordered it) . Should the court order expert evidence, each of the parties is entitled to appoint his own "technical counsel" for the purpose of assisting the experts appointed by the court and of submitting a separate report on the technical questions at issue.
