The fragmentation of forests is a consequence of human activities that intensively change the natural landscapes. In Brazil, there is a long-standing legal framework for native vegetation protection, called Forest Code. The last update is from 2012. The revisions incorporated in this restructured code (Law No. 12,651/12) encompassed new rules, rights and obligations for adequate land use management of productive systems and for environmental conservation and protection. An example of a protective measure was the creation of a Legal Reserve inside the rural properties and Areas of Permanent Protection around the watercourses. This study explored the effects of implementing the new code on the spatial and temporal evolution of forest cover fragmentation since the legal changes were set up. In that context, the area, perimeter and shape (circularity index) of forest fragments, as well as the buffer strips along watercourses, were assessed from 2010 to 2016 within the municipality of Ribeirão Preto, São Paulo state, Brazil. The assessment resorted to remote sensing techniques and visual inspection of orbital images. It was clear from the results that forest patches became more abundant but smaller, more dispersed and elongated, and that this route to fragmentation was hinged on a chaotic expansion of urban and agricultural areas. Important edge effects were anticipated from these results. The area numbers revealed that Ribeirão Preto was 7.95% covered with forest fragments in 2010, while this percentage rose to 8.03% in 2013 and reached 8.35% in 2016. Most of this increase occurred within a 30-meter wide buffer along the watercourses. This was a positive outcome. However, the numbers also revealed that forested areas smaller than 51 hectares increased from 71% in 2010 to 73% in 2016. The conclusions were that implementation of Law No. 12,651/12 is leading to an increase of forestland, but not yet promoting sustainability, namely through improved connectivity among fragments for reduction of edge effects and provision ecosystem services.