Code of Civil Procedure Article 330

Any person who falls within one of the cases provided in the first to the fifth subparagraphs inclusive of Article 32 cannot act as an expert witness, except where no other appropriate person may be appointed or such person has been designated by the parties by agreement.Where an expert witness refuses to give expert testimony for whatever reason other than those provided in the first paragraph of Article 307, the court may relieve him/her from the duty to act as an expert witness if the court considers the reason given to be justifiable.