The random distribution of pores in location, size and shape makes the fracture of porous materials a difficult problem. We address herein a simplified model of porous material as can be obtained for instance in ceramics by introducing organic or polymer particles prior to the sintering step. Resulting spherical pores are almost regularly located with a homogeneous distribution in size. A fracture criterion involving both toughness and tensile strength allows studying the competition between, on the one hand the crack blunting due to the pores and resulting in an apparent toughness enhancement, and on the other hand the weakening effect caused by an increasing volume fraction of pores.