National audience In this article we experimentally explore the extent to which individuals’ labour supply is influenced by tax rates. During the experiment, a participant, chosen randomly, should determine his/her offer of work knowing that part of his/her income will be collected for the benefit of another participant. We carried out four treatments according to the volume of work (high or low) and depending on whether the rate of taxation is determined by the computer or by the recipient of the levies. Experimental results show that high taxes incentivise individuals to reduce their labour supply. This effect is particularly important when the volume of work is high and the rate is determined by the recipient of the taxes.