Very long and detailed (over 2 months, several phone interviews and one in-person) but highly professional and at times highly enjoyable. This company employs top-notch scientists and topic of discussions was science and goal oriented. Very few personality questions. The only drawback were the long periods of silence between contacts. I felt things weren't moving and if I weren't so particular about the job I was looking for I might have given up. However, I had other pharma interviews and none came close to matching the scientific rigor at Sanofi.