Aquatic contaminations pose many problems for organisms and the functioning of ecosystems, mainly caused by agricultural activity including fungicides. It is in this context that we conducted an ecotoxicological study to evaluate the toxicity of a (FOLIETTE) fungicide, commonly used in Algeria, in a freshwater macrophyte (Iris pseudacorus L.) from natural marshes in the ‘'Bourdim region, El-Tarf located in the extreme northeast of Algeria'' by measuring certain physiological and biochemical parameters. The results obtained show that the addition of this fungicide, at different concentrations for 7 days of treatment, decreases the content of chlorophyll pigment and increases the accumulation of total proteins in different parts of the plant (roots and leaves). Similarly, a significant increase in some stress biomarkers such as total polyphenols, malondialdehyde (MDA) and glutathione (GSH). At the same time, the measurement of enzyme activity involved in the detoxification system shows a significant induction of guaiacol-peroxidase (GPX) activity, which plays an important role in mitigating oxidative damage, thus proving the tolerance of our plant model to this xenobiotic and consequently its possible use as a candidate for phytorepuration.