Reservoir appraisal is commonly a difficult task in fold and thrust belts. Thrust-related folding leads to the development of meso- to microscopic brittle structures that can significantly alter the porosity and permeability properties of reservoir rocks, thus influencing fluid migration and accumulation. The aim of this chapter is to describe at different scales the deformation associated to the development of the Chaudrons thrust-related anticline (Corbires, France) and to discuss its influence on reservoir quality. Pervasive solution cleavage sets at high angle to bedding (ATB) were found and measured along the fold. In addition, collected core samples were used to measure the rock physical properties (anisotropy of magnetic susceptibility and anisotropy of the P-wave velocity). The distribution of deformation in the anticline was used to identify three different deformational panels: crest, rounded forelimb, and constantly steeping forelimb. The crest is characterized by the lowest cleavage intensity. Nonpenetrative solution cleavages and the magnetic foliation are orthogonal to bedding. In the rounded forelimb, bedding dip progressively rotates from 0 to 60. Cleavage intensity progressively increases, and cleavage and magnetic foliation ATBs progressively increase from 80 to 120 and then remain constant in the steep forelimb. The timing of the development of mesoscale structures, as well as changes of physical properties occurring before and during folding, is also discussed.