11/2011-06/2015, PhD, supervised by Barbara Romanowicz; 07/2015-12/2017, postdoc, supervised by Éléonore Stutzmann. I was never officially his supervisor, but he worked with me on the sixth chapter of his thesis on the Born approximation and the influence of scattering on seismological data. This experiment became one of the axes of Ssu-Ting’s thesis, and Matthias co-authors the second paper we are preparing. To examine the effects of random heterogeneities on waveforms in global seismology, Matthias contributed a lot to improving my code “DSM Kernel Suite”. His contribution to the life of researchers and students at the institute must not be forgotten: he organised workshops and French language classes to support mental health, especially of students. He was the first member of the IPGP orchestra (now the PhiloGaïa Orchestra), which I initiated, and we also wrote a paper together on this subject. He works as a manager at a Paris-based software company (Tweag). With Milena and John, he organised a geophysics hackathon at IPGP (for the first time in 2019).