France has issued arrest warrants for two top Djibouti officials in connection with the mysterious death of a French judge in 1995.
Djibouti Chief Prosecutor Djama Souleiman and security chief Hassan Said are accused of interfering with witnesses in the investigation.
The burnt body of Bernard Borrel was found in just a T-shirt and underpants.
Djibouti authorities initially said his death was a suicide, but his widow says he was assassinated.
At the time of his death, Borrel was acting as a consultant to the Djibouti justice ministry.
France and Djibouti are close allies, with Djibouti hosting France's largest overseas military base, as well as a US anti-terror task force.
"The magistrates are showing that they are not afraid to seek the truth even if it is displeasing to the political authorities of France and Djibouti," said Olivier Morice, a lawyer for the Borrel family.
But Mr Said told the AFP news agency that Djibouti would not recognise the warrants.
"Djibouti will never bow to the wishes of the French justice in which my country no longer has confidence."
Earlier this year, Djibouti asked the International Court of Justice to rule that French investigators did not have the right to summon high-level witnesses, as they enjoyed diplomatic immunity.