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The aforementioned claim is revisited in the present study. The sensitivity to the top-quark electroweak couplings is estimated here with an optimal-observable analysis of the lepton angular and energy distributions of over a million events from ${\rm t\bar t}$ production at the FCC-ee, in the $\ell \nu {\rm q \bar q b \bar b}$ final states (with $\ell = {\rm e}$ or $\mu$), without incoming longitudinal beam polarization and with a centre-of-mass energy not significantly above the ${\rm t\bar t}$ production threshold.   Such a sensitivity can be understood from the fact that the top-quark polarization arising from its coupling to the Z is maximally transferred to the final state particles via the weak top-quark decay ${\rm t \to W b}$ with a 100\% branching fraction: the lack of initial polarization is compensated by the presence of substantial final state polarization, and by a larger integrated luminosity. A similar situation was encountered at LEP, where the measurement of total rate of ${\rm Z} \to \tau^+\tau^-$ events and of the tau polarization was sufficient to determine the tau couplings to the Z, regardless of initial state polarization~\cite{doi:10.1016/j.physrep.2005.12.006}. polarization~\cite{2006}.  This letter is organized as follows. In Section~\ref{sec:theory}, the reader is briefly reminded of the theoretical framework. The statistical analysis of the optimal observables is described in Section~\ref{sec:optimal}, and realistic estimates for the top-quark electroweak coupling sensitivities are obtained in Section~\ref{sec:sensitivities}, as a function of the centre-of-mass energy at the FCC-ee. The results are summarized in Section~\ref{sec:summary}, and prospects for further improvements are given.