According to Reuters, the appeal was lodged with the Court of Justice of the European Union on 4 December.

It aims to overturn the conclusion drawn by the EU General Court, confirming the European Commission’s 2015 findings that a 2012 tax ruling between Luxembourg and the firm constituted an illegal subsidy.

The commission concluded that the taxable profits for Fiat's Luxembourg unit could have been 20 times higher under normal market conditions

The last appeal decision, announced on 24 September, would force the manufacturer to pay up to €30m in unpaid taxes to the Luxembourg state.

Fiat Chrysler is one of a handful of multinationals targeted in an EU crackdown on tax avoidance practices. Luxembourg is awaiting a decision after appealing in 2018 against a decision regarding Engie (formerly GDF Suez).

The European Commission is also reportedly in the process of investigating a Luxembourg tax ruling with Huhtamaki Oyj’s (HUH1V.HE).