It is possible to trace the shape of a drum from its vibration modes. Similarly, it is possible to measure the 3D structure of the proton and access its elementary components, quarks and gluons, from observables obtained using deeply virtual Compton scattering experiments off the proton. By studying this scattering process, we can access this geometric information. This research topic is very active and mobilizes a large international theoretical and experimental community. As part of the PARTONS (PARtonic Tomography Of Nucleon Software) project, physicists from Irfu and NCBJ in Warsaw successively performed two detailed analyses using all the measurements associated with this process published since the early 2000s. This represents nearly 2600 measurement points and 30 observables from 6 different experiments. This work, published in the European Physical Journal C [1, 2], is now the most advanced analysis of these experimental data. New data, combined with new analysis methods, will enrich the PARTONS library in the future; these observables (Compton form factors) will make it possible to go one step further in the reconstruction of the proton structure in 3D.
 H. Moutarde, P. Sznajder et J. Wagner (2018). Border and skewness functions from a leading order fit to DVCS data. Eur. Phys. J. C78, 890.
 H. Moutarde, P. Sznajder et J. Wagner (2019). Unbiased determination of DVCS Compton Form Factors. Eur. Phys. J. C79, 614.