Since the beginning of the 1990s, liquid releases of gamma-emitting radionuclides from French nuclear facilities have generally fallen by almost 85%. Almost 65% of gamma-emitting liquid effluents released into freshwater rivers concerned the River Rhône (Southeast France), with around 85% of this originating from the Marcoule spent fuel reprocessing plant. Upstream of French nuclear plants, artificial radionuclides still detected by gamma spectrometry in 2006, include ¹³⁷Cs, ¹³¹I as well as ⁶⁰Co, ⁵⁸Co and ⁵⁴Mn in the case of the Rhine (Switzerland nuclear industries). In the wake of the fallout from the Chernobyl accident, ¹⁰³Ru, ¹⁰⁶Rh-Ru, ^110mAg, ¹⁴¹Ce and ¹²⁹Te were detected in rivers in the east of France. Some of these radionuclides were found in aquatic plants until 1989. In eastern France, ¹³⁷Cs activity in river sediments and mosses is still today two to three times greater than that observed in similar environments in western France. No ¹³⁴Cs has been detected upstream of nuclear plants in French rivers since 2001. Downstream of nuclear plants, the gamma emitters still detected regularly in rivers in 2006 are ¹³⁷Cs, ¹³⁴Cs, ⁶⁰Co, ⁵⁸Co, ^110mAg, ⁵⁴Mn, ¹³¹I, together with ²⁴¹Am downstream of the Marcoule spent fuel reprocessing plant. Alpha and beta emitters such as plutonium isotopes and ⁹⁰Sr first entered freshwaters at the early 1950s due to the leaching of soils contaminated by atmospheric fallout from nuclear testing. These elements were also introduced, in the case of the Rhône River, via effluent from the Marcoule reprocessing plant. Until the mid 1990s, plutonium isotope levels observed in the lower reaches of the Rhône were 10 to 1000 times higher than those observed in other French freshwaters. Data gathered over a period of almost thirty years of radioecological studies reveal that the only radionuclides detected in fish muscles are ¹³⁷Cs, ⁹⁰Sr, plutonium isotopes and ²⁴¹Am. At the scale of the French territory, there is no significant difference since the mid 1990s between ¹³⁷Cs activity observed downstream of nuclear facilities and that observed upstream, whether in sediments, mosses and fish. Finally, this study highlights that the natural radioactivity of surface freshwaters are around 25 times greater than artificial radioactivity from gamma emitters. However, non gamma emitters released by nuclear industries, such as ³H, may lead to artificial activity levels 2 to 20 times higher than natural levels.