Measurements of the Hall effect and the resistivity on precisely-patterned YBCO thin films in magnetic fields B from 0.5 to 6 T oriented parallel to the sample crystallographic c axis reveal a sign reversal of the Hall coefficient for B <= 3 T. The data are compared to the full, quantitative expressions based on the renormalized fluctuation model for the Hall conductivity. The model offers a satisfactory understanding of the experimental results, for moderate fields and temperatures near the

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... tical region, provided that the inhomogeneity of the critical temperature distribution is also taken into account. We also propose an approach how vortex pinning that strongly affects the magnitude of the Hall coefficient can be incorporated in the model.