Café Philo at the French Institute in London takes place every Saturday, alternately in French and English. There are typically 30 participants, representing all age groups and many nationalities; they choose the topic of the conversation at the start of the meeting (a bonus for those who arrive punctually  )  Topics cover a broad range from ‘pure philosophy’ to social issues. Like all café philos the French Institute one is a good place to make friends, especially for new arrivals in London. 
For more information, email cmichel@cmichel.com