The recommendation came in a report on Stellantis's upcoming annual general meeting seen by Reuters on Tuesday.
The world's third largest carmaker earlier this year said Tavares' total pay for 2022 amounted to 14.9 million euros ($16.3 million), 14% lower than a 17.4 million euro compensation for the previous year.
In the report, ISS said the proposed remuneration was in line with market practice, but raised concerns including for a "lack of clarity regarding the key perquisites allocated to both the CEO and chairman".
ISS added that concerns also remained about some incentives introduced in 2021. Although no payout occurred in the past fiscal year, if performance targets to 2025 were achieved, they could lead to a 40 million euro payout, at current market value, on top of the CEO's existing pay package.
It "may be considered excessive once vested," it said.
The executive remuneration package for 2021, which prompted criticism from trade unions and politicians, especially in France, was rejected by over 52% of Stellantis investors in a consultative vote at last year's annual general meeting.
The group will hold its meeting to approve its 2022 results on April 13, with investors called to take part in an advisory vote on the group's new remuneration package.
($1 = 0.9119 euro)
(Reporting by Giulio Piovaccari; Editing by Jonathan Oatis)
