Ceinture 81 to 93 were a class of thirteen 4-6-4T ("Baltic") tank locomotives designed by Gaston du Bousquet of the Chemins de fer du Nord for the Syndicat d'Exploitation des Chemins de fer de Ceinture de Paris.

They were almost identical to the 3.801 to 3.865, series that the Nord had built for itself in its own workshops at La Chapelle (fr) and Hellemmes.

The Ceinture locomotives were built in 1909 by Société française de constructions mécaniques.

In addition 85 received Caprotti rotary-cam valve gear.

Eleven locomotives received feedwater heaters: eight, 81 and 85 to 91, were by ACFI; three 83, 84 and 93 were by Caille Potonie.