  We present a planar spectro-polarimeter based on Fabry-P{\'e}rot cavities
with embedded polarization-sensitive high-index nanostructures. A
$7~\mu$m-thick spectro-polarimetric system for 3 spectral bands and 2 linear
polarization states is experimentally demonstrated. Furthermore, an optimal
design is theoretically proposed, estimating that a system with a bandwidth of
127~nm and a spectral resolution of 1~nm is able to reconstruct the first three
Stokes parameters \textcolor{black}{with a signal-to-noise ratio of -13.14~dB
with respect to the the shot noise limited SNR}. The pixelated
spectro-polarimetric system can be directly integrated on a sensor, thus
enabling applicability in a variety of miniaturized optical devices, including
but not limited to satellites for Earth observation.
