3-dimensional (3D) halide perovskites AMX3 (A: organic cation, M: metal ion, X: halide) have shown spectacular results in optoelectronic devices. However, they offer limited choice of metals and organic cations, which limits the chemical design of optimal materials. This is not the case of lower dimensional materials, e.g. layered (2D) halide perovskites (LHPs) [1], that impose far less constraints over the organic spacer. It then become possible to associate the exceptional optoelectronic properties of halide perovskites with chiral cations to reach promising materials for chiroptical and magnetochiral applications [2]. Here, we report joint experimental and theoretical investigations of LHPs with exceptional (i) chiroptical, and (ii) magnetochiral properties. Firstly, the enantiopure 3BrMBA2PbI4 (MBA = methylbenzylammonium) perovskite thin films exhibit external photoluminescence quantum efficiency as high as 39% and circularly polarized photoluminescence up to 52%, at room temperature [3]. Next, we consider a series of chiral lead-bromide networks which crystallize in enantiomorphic polar space groups P41212 and P43212 for the R and S enantiomers, respectively [4]. Chirality-induced spin selectivity (CISS) effect measurements performed over those materials by magnetic conducting-probe atomic force microscopy (mc-AFM) reveal a spin polarization of about 40% [4]. We use a set of experimental characterizations (e.g. single-crystal x-ray diffraction), and theoretical tools (semi-empirical modeling and density-functional theory based calculations) to describe the chiral-related properties of these LHPs and help the cation engineering of efficient chiral halide perovskites. Acknowledgment. The work was performed with funding from Agence Nationale pour la Recherche under grant ANR-18-CE05-0026 (MORELESS project), the European Union’s Horizon 2020 program, through an innovation action under grant agreement no. 861985 (PeroCUBE) and a FET Open research and innovation action under the grant agreement no. 899141 (PoLLoC). This work was granted access to the HPC resources of TGCC under the allocations 2022-A0130907682 made by GENCI. [1]B. Saparov, D. B. Mitzi, Chem. Rev. 2016, 116, 4558; L. Pedesseau, M.K. et al., ACS Nano 2016, 10, 9776; C. Katan, N. Mercier, J. Even, Chem. Rev. 2019, 119, 3140. [2]Y.-H. Kim et al., Science 2021, 371, 1129 ; M. K. Jana et al., Nat. Commun. 2021, 12, 4982 ; G. Long et al., Nat. Rev. Mater. 2020, 5, 423 ; H. Lu, Z. V. Vardeny, M. C. Beard, Nat. Rev. Chem. 2022, 6, 470. [3]S. Liu, M.K. et al., submitted manuscript. [4]A. Abhervé, M.K. et al., submitted manuscript.