A monolithic membrane-type filtration structure for filtering liquids, comprising: - a support formed of a porous inorganic material of permeability K s , said support having a tubular overall shape with a main axis, an upstream base, a downstream base, a peripheral wall delimiting an internal part; - a plurality of passages parallel to the main axis of the support, formed in the internal part of the support, said passages being separated from one another by internal walls formed of the porous inorganic material; - all said passages being open at their upstream or downstream ends in the direction in which said liquid circulates, - the filtered liquid being removed via said peripheral wall, - a membrane of permeability K m and of mean thickness t m covering the internal surface of the passages; characterized in that its external hydraulic diameter Ø f satisfies the relationship : ∅ f = α × A + B × log 10 K s × t m / K m in which α is a coefficient comprised between 0.85 and 1.15, and A = − 21570 × e int 2 − 18.6 × D h + 19.0 × e int − 2.5 × e ext + 0.1244 B = − 11760 × D h × e int + 9.7 × e int + 3.1 × e ext + 0.04517 in which: D h is the mean hydraulic diameter of the passages, e int is the minimum thickness of the internal walls between the passages, e ext is the minimum thickness of the peripheral wall of the filter, t m , Ø f , e int , e ext and D h being expressed in meters and K s and Km being expressed in m 2 the permeabilities of the support Ks and the membrane Km being defined on the basis of the Kozeny-Carman relationship by the following formula: K = (PO 3 ×D 50 2 )/[180 × (1-PO) 2 ] where PO is the open porosity and D 50 is the median pore diameter, said open porosity and median pore diameter being determined by mercury porosimetry in accordance with the present description. - a support formed of a porous inorganic material of permeability K s , said support having a tubular overall shape with a main axis, an upstream base, a downstream base, a peripheral wall delimiting an internal part; - a plurality of passages parallel to the main axis of the support, formed in the internal part of the support, said passages being separated from one another by internal walls formed of the porous inorganic material; - all said passages being open at their upstream or downstream ends in the direction in which said liquid circulates, - the filtered liquid being removed via said peripheral wall, - a membrane of permeability K m and of mean thickness t m covering the internal surface of the passages; D h is the mean hydraulic diameter of the passages, e int is the minimum thickness of the internal walls between the passages, e ext is the minimum thickness of the peripheral wall of the filter, t m , Ø f , e int , e ext and D h being expressed in meters and K s and Km being expressed in m 2 the permeabilities of the support Ks and the membrane Km being defined on the basis of the Kozeny-Carman relationship by the following formula: K = (PO 3 ×D 50 2 )/[180 × (1-PO) 2 ] where PO is the open porosity and D 50 is the median pore diameter, said open porosity and median pore diameter being determined by mercury porosimetry in accordance with the present description. <EOS>