An electronic circuit including a surface intended to be attached to another electronic circuit by hybrid molecular bonding. The electronic circuit includes an electrically-insulating layer exposed on the surface, and, distributed in the electrically-insulating layer, first electrically-conductive bonding pads exposed on a first portion of the surface, the density of the first bonding pads on the first portion of the surface being smaller than 30%, and at least one electrically-conductive test pad, exposed on a second portion of the surface containing a square having a side length greater than 30 μm. The density of electrically-conductive material of the test pad exposed on the second portion of the surface is in the range from 40% to 80%.