Senior Djiboutian officials have been implicated in the case and the judge's widow has accused the east African country's president of ordering her husband's murder.

President Ismael Omar Guelleh has denied the charge and in turn accused France of trying to destabilize his country.

In the world court case, Djibouti has argued that France violated two bilateral cooperation agreements by withholding evidence about the death of the magistrate, Bernard Borrel, who was an adviser to the Djibouti Justice Ministry.

Djibouti, which hosts France's largest military base in Africa, also has claimed immunity for two senior officials sought by a French investigating magistrate in the case for allegedly bribing witnesses.

In addition, France has asked to question Guelleh but has conceded the president cannot be summoned against his will.