A reliable source told PANA Monday in Paris that the arrests took place between Saturday and Sunday in the Khartoum areas of Souk Elchaabi, Hadj Youssouf, Am Kado 19 and Souk Libiya.
The arrests came in the wake of the killing last Thursday of the Chadian Consul in El Geneina, Darfur (western Sudan) near the border with Chad by unidentified gunmen.
The diplomat was first taken to a hospital in El Geneina, then transferred to Adre and later to N'djamena, where he died.
Relations between Sudan and Chad have been strained of late, with N'djamena accusing Khartoum of harbouring more than 3,000 armed Chadian rebels.
The Chadian government has since announced the suspension its mediation in the Sudan talks to settle the crisis in Darfur crisis, but later changed its mind.