EX-99.1

Exhibit 99.1

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Constellium posts Annual General Meeting Materials

Paris, April 21, 2021 – Constellium SE (NYSE: CSTM) (the “Company”) today announced that the notice and agenda and other documents for the Company’s Annual General Meeting of Shareholders to be held on May 11, 2021, at 16:00 CET (10:00 AM EDT), are available on its website at www.constellium.com and will be available free of charge at the offices of the Company by contacting the Corporate Secretary at cstm.corporatesecretary@constellium.com.

About Constellium

Constellium (NYSE: CSTM) is a global sector leader that develops innovative, value added aluminium products for a broad scope of markets and applications, including aerospace, automotive and packaging. Constellium generated €4.9 billion of revenue in 2020.

www.constellium.com

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