This paper is dealt with the problem of decentralized prescribed performance control (PPC) for the interconnected systems composed of feedback linearizable systems. Without the restrictive conditions in the related studies, the interconnections need merely to be continuous in this paper. Moreover, this study is focused on the model-free control design, i.e., no prior knowledge of the system model is used for the controller, except for the most fundamentally structural information. To solve the problem, a novel decentralized model-free PPC approach is developed. The skilful combination of the orientation function and the barrier function yields a model-free PPC, without approximation, identification, adaptation, etc. By adopting the dialectic by contradiction to establish the control performance, instead of the Lyapunov stability theory, it is revealed that the proposed control is inherently robust against the interconnections. The simulation results on the inverted double pendulums demonstrate the effectiveness of our approach.