Conferences list (computer science)

Open Source

RMLL (Francophone countries, July)
FOSDEM (Belgium, February)
Solutions Linux (Paris, May)
Open world forum (Paris, October)
OSCON (O'Reilly convention, USA, July)
LinuxCon Europe (Europe, October)

System Administration and devops

LISA (United States, December)
LOAD (Belgium)
devopsdays (International, Paris event : 2013/04/18)
Velocity (International, London event : 2013/11/13)
FLOSS UK (LISA little sister, UK, March)
CloudConf (June 7, 2013)
Cloud Computing World Expo (2013/04/10)
Config Management Camp

Computer Security

SSTIC (Rennes, June)

Software Development

Djangocong (France)
PyconFR (Python programming, Paris, September)
Devoxx (Java programming, Europe)
Djangocon Europe 2014 (This year in France)
Europython 2014 (Germany)

Web

Paris Web (Paris, October)
Sud web (South of France, May)

Misc

TEDxParis (Paris, September)