  We explicitly determine the large deviation function of the energy flow of a
Brownian particle coupled to two heat baths at different temperatures. This toy
model, initially introduced by Derrida and Brunet [B. Derrida and E. Brunet, in
"Einstein aujourd'hui", EDP Sciences, 2005], allows not only to sort out the
influence of initial conditions on large deviation functions but also to
pinpoint various restrictions bearing upon the range of validity of the
Fluctuation Relation.
