the invention relates to a microfluidic circuit including at least one microchannel for the flow of a first fluid conveying drops or bubbles of at least one second fluid , characterized in that the height of the microchannel is sized so as to crush the drops or bubbles during the movement thereof , and in that the microchannel comprises at least one trough , extending at least partially in the direction of flow of the first fluid or an area for trapping drops or bubbles , said area or the trough having a height that is greater than the height of the microchannel , such that at least some of the drops or bubbles of the second fluid in the microchannel are drawn and guided into the trough or into the trapping area .