  We here address the question of restoration of uniqueness in mean-field games
deriving from deterministic differential games with a large number of players.
The general strategy for restoring uniqueness is inspired from earlier similar
results on ordinary and stochastic differential equations. It consists in
randomizing the equilibria through an external noise.
  As a main feature, we choose the external noise as an infinite dimensional
Ornstein-Uhlenbeck process. We first investigate existence and uniqueness of a
solution to the noisy system made of the mean-field game forced by the
Ornstein-Uhlenbeck process. We also show how such a noisy system can be
interpreted as the limit version of a stochastic differential game with a large
number of players.
