  $^{75}$As, $^{87}$Rb and $^{85}$Rb nuclear quadrupole resonance (NQR) and
$^{87}$Rb nuclear magnetic resonance (NMR) measurements in RbFe$_2$As$_2$
iron-based superconductor are presented. We observe a marked broadening of
$^{75}$As NQR spectrum below $T_0\simeq 140$ K which is associated with the
onset of a charge order in the FeAs planes. Below $T_0$ we observe a power-law
decrease in $^{75}$As nuclear spin-lattice relaxation rate down to $T^*\simeq
20$ K. Below that temperature the nuclei start to probe different dynamics
owing to the different local electronic configurations induced by the charge
order. A fraction of the nuclei probes spin dynamics associated with electrons
approaching a localization while another fraction probes activated dynamics
possibly associated with a pseudogap. These different trends are discussed in
the light of an orbital selective behaviour expected for the electronic
correlations.
