Romain Coltel is the lead product manager in a french startup, Alsid IT, tackling Active Directory problems down to the core, and he's thus currently doing a lot of research and development on various Active Directory technologies. He's also teaching the well-received SANS SEC660 in France, each time with the author's congratulations at the end of the session.
Before that, he was acquiring his experience in the french National Cybersecurity Agency (ANSSI) as an IT auditor, where he performed penetration testing, various security researches and tools development. As a development example, he's the lead developer of dislocker, a tool to decrypt BitLocker-encrypted partitions on Linux, OSX and FreeBSD. He also implemented the AES-XEX and -XTS modes for the famous mbedTLS library.