The fees and expenses of physicians, including coroners and other physicians in the employ of the state or its political subdivisions, appointed by a court to make a mental examination and report prior to commitment shall be fixed by the court in an amount not less than the fees set forth in R.S. 13:5706 and shall be paid by the parish where the prosecution was instituted. The fee paid to the coroner or other physician in the employ of the state shall be in addition to his salary. Use of the facilities of a state mental institution in making the mental examination shall be without cost to the parish.