Article 17 of the Lugano Convention

1. If the parties, one or more of whom is domiciled in a Contracting State, have agreed that a court or the courts of a Contracting State are to have jurisdiction to settle any disputes which have arisen or which may arise in connection with a particular legal relationship, that court or those courts shall have exclusive jurisdiction. Such an agreement conferring jurisdiction shall be either:

(a) in writing or evidenced in writing, or
(b) in a form which accords with practices which the parties have established between themselves, or
(c) in international trade or commerce, in a form which accords with a usage of which the parties are or ought to have been aware and which in such trade or commerce is widely known to, and regularly observed by, partiesto contracts of the type involved in the particular trade or commerce concerned.
Where such an agreement is concluded by parties, none of whom is domiciled in a Contracting State, the courts of other Contracting States shall have no jurisdiction over their disputes unless the court or courts chosen have declined jurisdiction.

2. The court or courts of a Contracting State on which a trust instrument has conferred jurisdiction shall have exclusive jurisdiction in any proceedings brought against a settlor, trustee or beneficiary, if relations between these persons or their rights or obligations under the trust are involved.

3. Agreements or provisions of a trust instrument conferring jurisdiction shall have no legal force if they are contrary to the provisions of Article 12 or 15, or if the courts whose jurisdiction they purport to exclude have exclusive jurisdiction by virtue of Article 16.

4. If an agreement conferring jurisdiction was concluded for the benefit of only one of the parties, that party shall retain the right to bring proceedings in any other court which has jurisdiction by virtue of this Convention.

5. In matters relating to individual contracts of employment an agreement conferring jurisdiction shall have legal force only if it is entered into after the dispute has arisen.