ParticleTrieur is a cross-platform java program to help organise, label, process and classify images, particularly for particle samples such as microfossils. It can be used for both the creation of the training set required to make a CNN classifier, and classification of image using a trained CNN. It also includes some image processing functions, morphology calculations and statistical graph generation. ParticleTrieur allows the user to configure and launch training using the MISO library. See https://particle-classification.readthedocs.io/en/latest/