A method for detecting a fault in a photovoltaic module includes determining a matrix of temperatures of the photovoltaic module, the matrix being obtained after dividing the module into a plurality of thermal zones and assigning a temperature to each thermal zone; detecting at least one hot thermal zone from among the plurality of zones of the module; determining a surface area ratio between the surface area of the detected hot thermal zone and the total surface area of the module; performing a first comparison of the surface area ratio with a coefficient dependent on the number of bypass diodes present in the module; and determining the type of fault from the result obtained in said first comparison.