We study the properties of Braess's paradox in the context of the model of
congestion games with flow over time introduced by Koch and Skutella. We
compare them to the well known properties of Braess's paradox for Wardrop's
model of games with static flows. We show that there are networks which do not
admit Braess's paradox in Wardrop's model, but which admit it in the model with
flow over time. Moreover, there is a topology that admits a much more severe
Braess's ratio for this model.