Inclusive $\jpsi$ polarization parameters as a function of transverse momentum for Pb--Pb collisions at $\ensuremath{\sqrt{s_{_{\mathrm{NN}}}}}=$ 5.02 TeV, compared with results obtained in pp collisions by ALICE at $\ensuremath{\sqrt{s}}=$ 8 TeV \cite{Acharya:2018uww} and by LHCb for prompt $\jpsi$ at $\ensuremath{\sqrt{s}}=$ 7 TeV \cite{Aaij:2013nlm} (markers were  shifted horizontally by +0.3 GeV/\textit{c} for better visibility) in the rapidity interval $3<y<3.5$. The error bars represent the total uncertainties for the pp results, while for Pb--Pb statistical and systematic uncertainties are plotted separately as a vertical bar and a shaded box, respectively. In the left part of the plot the polarization parameters in the helicity reference frame are reported, in the right those for the Collins-Soper frame.