Treat it as a professional conversation even if it is described as a coffee chat. Recruiting may be checking interest, fit, timing, location, or simply building the candidate relationship.

Prepare a concise background, why BCG, why the office, and a few thoughtful questions. You do not need to turn the conversation into a memorized fit interview.

Most importantly, know your own application. Anything on the resume can become part of the discussion even when the call feels casual.

Mine was relaxed but they definitely asked why the office.

Professional casual is how I would describe it.