In its outer form, this practice A/T mine looks a lot like the German Tellermine35 Üb of WW2.
It differs in the fact that the top can be taken off to insert a practice smoke charge.
These mines were issued 5 in one case, measuring 80x45x43, which weighed some 50kilos.

Diameter : 320mm
Height : 85mm
Weight : 8kilo
Filling : 400gram blackpowder charge.

Photos © M. Jochoms

The fuze used with this mine was the Allumeur a pression modele 35.

This mine appears to be the same as the Dutch Nr.27 practice A/T mine.

Photos below © Franck.