(Pb_0.96La_0.04)(Zr_0.95Ti_0.05)_0.99O₃ ceramics were successfully elaborated by the solid-sate reaction method. The pure perovskite phase was obtained, comprising both rhombohedral (R3c) and orthorhombic (Pbam) crystallographic structures, as determined by x-ray diffraction and Raman spectroscopy analyses. The rhombohedral and orthorhombic structures were carefully attributed to the ferroelectric (FE) and antiferroelectric (AFE) phases, respectively. The room temperature electromechanical performances of the samples were particularly investigated at the nanoscale level by using piezoresponse force microscopy (PFM). The measurement of PFM domain patterns evidenced spontaneous piezoelectric and ferroelectric activities as well as regions with no piezoresponse, in agreement with the coexistence of FE and AFE phases. By means of the spectroscopic mode of the PFM used in on- and off-field methods, very specific piezoloops were recorded. Square-shaped hysteresis loops for phase signal and butterfly-like shape loops for amplitude activity were obtained under and at zero bias when probing ferroelectric regions, while on-field piezoloops displaying double hysteresis for phase signal were detected and assigned to the stable antiferroelectric phase. Finally, the signature of metastable antiferroelectric phase was also identified through in-field and remnant loops measurements. These results further provided the phases coexistence, concurrently unveiling intricate nanoscale electrical characteristics (both stable and metastable AFE behaviors) at room temperature. Furthermore, these data suggest that PFM proves to be a robust technique for investigating local antiferroelectricity in such complex ceramic oxides.