Note that Accenture hiring can take quite a while -- in my case, about five months (!).
Accenture engineers go through several interviews: the initial recruitment interview to verify information in the CV, a "behavioural" interview by HR to ferret out "nutcases" ;-), a primary technical interview by the hiring team (which includes the team leader and another team member) -- this is usually a face-to-face interview. The first two interviews are usually over the phone.
After candidates pass the first interviews, they go through client interviews, i.e. Accenture's clients get to screen candidates. This is not the case for all Accenture projects, though -- only for clients with specific requirements. For managed services, Accenture handles the whole screening process.
There are usually three client interviews, again depending on the requirements, with varying -- and most of the time, increasing -- levels of difficulties. These interviews are done over the phone as the clients are usually off-shore. There are instances that Accenture flies in the clients to screen candidates.