# EDGAR Filing Document

**Accession Number:** 0001563411
**File Stem:** 0001563411-26-000032
**Filing Date:** 2026-1
**Character Count:** 8067
**Document Hash:** 4afbd3c40928a814b0e4f5394b97cf92
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001563411-26-000032.hdr.sgml**: 20260102

**ACCESSION NUMBER**: 0001563411-26-000032

**CONFORMED SUBMISSION TYPE**: 3

**PUBLIC DOCUMENT COUNT**: 3

**CONFORMED PERIOD OF REPORT**: 20260101

**FILED AS OF DATE**: 20260102

**DATE AS OF CHANGE**: 20260102

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** BROOKS MARTHA
- **CENTRAL INDEX KEY:** 0001269707

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-35931
- **FILM NUMBER:** 26500708

**MAIL ADDRESS:**
- **STREET 1:** 10560 DR. MARTIN LUTHER KING JR. ST. N.
- **CITY:** ST. PETERSBURG
- **STATE:** FL
- **ZIP:** 33716
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** CONSTELLIUM SE
- **CENTRAL INDEX KEY:** 0001563411
- **STANDARD INDUSTRIAL CLASSIFICATION:** SECONDARY SMELTING & REFINING OF NONFERROUS METALS [3341]
- **ORGANIZATION NAME:** 04 Manufacturing
- **EIN:** 000000000
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** WASHINGTON PLAZA
- **STREET 2:** 40-44 RUE WASHINGTON
- **CITY:** PARIS
- **STATE:** I0
- **ZIP:** 75008
- **BUSINESS PHONE:** 33-1-73-01-46-51

**MAIL ADDRESS:**
- **STREET 1:** WASHINGTON PLAZA
- **STREET 2:** 40-44 RUE WASHINGTON
- **CITY:** PARIS
- **STATE:** I0
- **ZIP:** 75008

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Constellium SE
- **DATE OF NAME CHANGE:** 20190628

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Constellium N.V.
- **DATE OF NAME CHANGE:** 20130521

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Constellium Holdco B.V.
- **DATE OF NAME CHANGE:** 20121130

## Ex-24

![](brookscstm-section16powe001.jpg)

POWER OF ATTORNEY I, Martha Brooks, am a director of Constellium SE ("CSTM") and, as such, I am required to file with the U.S. Securities and Exchange Commission ("SEC") one or more Forms 3, 4, and 5 under Section 16 of the Securities Exchange Act of 1934, as amended ("Section 16"), and the rules promulgated by the SEC under Section 16, and Form 144 under Rule 144 promulgated by the SEC under the Securities Act of 1933, as amended ("Rule 144"). I hereby constitute and appoint Kristine Carpenter as my true and lawful attorney-in-fact to: 1. Do and perform any and all acts for and on my behalf which may be necessary or desirable to prepare, complete, execute, and file Forms 3, 4, 5, or 144, or any amendment to those forms, on a timely basis; 2. Execute such forms or any amendments to those forms for me in my name and file such forms and amendments with the SEC and any stock exchange or similar authority as required by law or rule for and on my behalf; and 3. Take any other action of any type whatsoever in connection with the foregoing which, in the opinion of my attorney-in-fact, may be of benefit to, in the best interest of, or legally required by me, it being understood that the documents executed by my attorney-in-fact on my behalf pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as my attorney- in-fact may approve in her discretion. I hereby grant to my attorney-in-fact full power and authority to do and perform any and every act and thing whatsoever requisite, necessary, advisable, or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as I might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that my attorney-in-fact, or my attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be done by virtue of this Power of Attorney and the rights and powers herein granted. I acknowledge that (i) my attorney-in-fact, in serving in such capacity at my request, is not assuming, nor is CSTM assuming, any of my responsibilities to comply with Section 16 and Rule 144, any associated liability, or any of my liability for disgorgement of profits under Section 16, and (ii) this Power of Attorney does not relieve me from responsibility for compliance with my obligations under Section 16 and Rule 144, including, without limitation, the reporting requirements under Section 16 and Rule 144. This Power of Attorney shall remain in full force and effect until I am no longer required to file under Section 16 or Rule 144, unless (i) earlier revoked by me in a signed writing delivered to my attorney-in- fact, or (ii) upon my attorney-in-fact's retirement or termination of employment with CSTM. A photocopy of this signed original shall be deemed to be, and should be accepted as, an original. _________________________ Martha Brooks Date: September _, 2025 Signature: Email: Martha Finn Brooks (Sep 23, 2025 21:48:32 GMT+3) mfbrooks1@me.com

------

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 3

### INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>BROOKS MARTHA<br><sub>(Last) (First) (Middle)</sub><br>300 EAST LOMBARD STREET<br>SUITE 1710<br><sub>(Street)</sub><br>BALTIMORE, MD 21202<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>CONSTELLIUM SE [ CSTM ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2026-01-01 | **4. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director   [ ] 10% Owner<br>[ ] Officer (give title below)   [ ] Other (specify below)<br>_ _ | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities Beneficially Owned

---

|  |  |  |  |
| --- | --- | --- | --- |
| 1. Title of Security | 2. Amount of Securities Beneficially Owned | 3. Ownership Form | 4. Nature of Indirect Beneficial Ownership |
| Ordinary shares | 97741 | D |  |
| Ordinary shares | 22000 | I | By spouse |
| Ordinary shares | 92000 | I<sup>(1)</sup> | Family limited partnership |

---

## Table II - Derivative Securities Beneficially Owned

---

|  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 3. Title and Amount of Underlying Securities | 3. Title and Amount of Underlying Securities | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
|  |  |  |  |  |  |  |  |

---

### Footnotes:

(1) The Reporting Person disclaims beneficial ownership of these securities except to the extent of her pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16.

**Signature:** /s/ Kristine Carpenter, Attorney-in-Fact for Martha Brooks  
**Date:** 2026-01-02

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**