Exhibit 10.10.1

Execution Version

Dated
27 May 2016

GE Capital Bank AG

Heinrich-von-Brentano-Str. 2,
 55130 Mainz, Germany

and

Constellium Valais S.A. Sierre,

3960 Sierre,





AMENDEMENT AGREEMENT

to a Factoring Agreement (dated 16 December 2010)







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Execution Version



This Amendment Agreement (the Agreement) is dated 27 May 2016, and entered into
between



|(1) | GE CAPITAL BANK AG, Heinrich-von-Brentano-Str. 2, 55130 Mainz, Germany, (hereafter referred
to as GE CAPITAL); and
|--- | --------------------------------------------------------------------------------------------------------------------



|(2) | Constellium Valais S.A., Sierre, a société anonyme incorporated under the laws of Switzerland with registered address at 3960 Sierre, registered under number CH-626.3.000.048-9. (hereafter referred to as the Originator).
|--- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

GE CAPITAL and
the Originator are hereafter referred to as the Parties.

WHEREAS:



|(1) | GE CAPITAL as purchaser and the Originator as seller entered into a factoring agreement on 16 December 2010, pursuant to which the Originator sells certain receivables to GE CAPITAL (the Factoring
Agreement).
|--- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



|(2) | GE CAPITAL has entered into a factoring agreement with Constellium Extrusions Deutschland GmbH, a limited liability company, with registered office at Bildstraße 4, 74564 Crailsheim, registered in the commercial
register (Handelsregister) of the local court (Amtsgericht) of Ulm under register number HRB 670619, on 16 December 2010 and has also entered into a factoring agreement with Constellium Singen GmbH, a limited liability company,
with registered office at Alusingen-Platz 1, 78224 Singen, registered in the commercial register (Handelsregister) of the local court (Amtsgericht) of Freiburg under register number HRB 540034, on 16 December 2010 (amended and
restated on 26 March 2014) and has also entered into a factoring agreement with Constellium Extrusions Decin s.r.o., a company incorporated and existing under the laws of the Czech Republic, with its registered office at Ùsteckà
751/37, Děčin V-Rozbělesy, 405 02 Děčin, Czech Republic, identification number 183 80 654, registered in the Commercial Register maintained by the Regional Court in Ùsti nad
Labem under file number C 301, on 26 June 2015.
|--- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



|(3) | On 26 June 2015, GE CAPITAL has entered into Amendment Agreements with the Originator, Constellium Extrusions Deutschland GmbH, Constellium Singen GmbH and Constellium Extrusions Decin s.r.o. to set a total
aggregate Maximum Commitment under the Factoring Agreement and the respective other factoring agreements.
|--- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



|(4) | GE CAPITAL will enter into a factoring agreement on or about the date hereof with Constellium Rolled Products Singen GmbH & Co. KG, registered with the commercial register (Handelsregister) of the local
court (Amtsgericht) of Freiburg i.Br., with registration number HRA 704399, having its registered seat at Alusingen-Platz 1, 78224 Singen, Germany.
|--- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



|(5) | In the context of the factoring agreement to be entered into between GE CAPITAL and Constellium Rolled Products Singen GmbH & Co. KG, the Parties have agreed to amend the Factoring Agreement with respect to the
Maximum Commitment (as defined in the Factoring Agreement).
|--- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



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Execution Version



GE CAPITAL and the Originator have agreed to enter into this Agreement in order to amend the Factoring
Agreement in accordance with this Agreement.



|1. | Definitions
|-- | -----------

Terms in italics have the meaning ascribed to them in the Factoring
Agreement, unless otherwise defined herein.



|2. | Amendment to the Factoring Agreement
|-- | ------------------------------------

Schedule 1 (Terms and Conditions) clause 4
(Maximum Commitment) shall be amended in whole and read as follows:

GE CAPITAL will set a maximum limit for each of
Constellium Singen GmbH, Constellium Extrusions Deutschland GmbH, Constellium Valais S.A, Constellium Extrusions Děčin s.r.o. and Constellium Rolled Products Singen GmbH & Co. KG whereby the total aggregate Maximum Commitment
under the respective factoring agreements between GE CAPITAL and Constellium Singen GmbH, Constellium Extrusions Deutschland GmbH, Constellium Valais S.A., Constellium Extrusions Děčin s.r.o. and Constellium Rolled Products Singen
GmbH & Co. KG amounts to 115.000.000.00 EUR (one hundred fifteen million Euro) and the Maximum Commitment for Constellium Extrusions Déćin s.r.o. may not exceed 15.000.000,00 EUR (fifteen million Euro). The respective Maximum
Commitment can be changed upon request of the respective originator(s).



|3. | PARTIAL INVALIDITY; WAIVER
|-- | --------------------------



|3.1 | Invalidity
|--- | ----------

If any provision of this Agreement should be or become invalid or
unenforceable in whole or in part, this shall not affect the validity or enforceability of the remaining provisions hereof. The invalid or unenforceable provision shall be deemed replaced by that provision which best meets the intent and the
economic purpose of the void or unenforceable provision.



|3.2 | Waiver
|--- | ------

No failure to exercise, nor any delay in exercising, on the part of the
Originator or GE CAPITAL, any right or remedy hereunder shall operate as a waiver thereof, nor shall any single or partial exercise of any right or remedy prevent any further or other exercise thereof or the exercise of any right or remedy. The
rights and remedies provided hereunder are cumulative and not exclusive of any rights or remedies provided by law.



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Execution Version



|4. | APPLICABLE LAW; JURISDICTION
|-- | ----------------------------



|4.1 | Applicable Law
|--- | --------------

This Agreement and all obligations arising out of or in connection with
this Agreement shall be governed by and construed in accordance with the laws of the Federal Republic of Germany.



|4.2 | German Courts
|--- | -------------

The courts of Mainz have exclusive jurisdiction to settle any dispute
arising out of or in connection with this Agreement (including a dispute regarding the existence, validity or termination of this Agreement or the consequences of its nullity).



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Execution Version



SIGNATORIES



|                               |  |                                        |  |  |  |                                 
|------------------------------ |  | -------------------------------------- |  |  |  | --------------------------------
|GE CAPITAL BANK AG            
|                               |  |                                        | 
|                               |  | LOGO                                   |  |  |  | LOGO                            
|                               |  |                                        |  |  |  |                                 
|                               |  |                                        | 
|Signed by:                     |  | Philipp Schiemann                      |  |  |  | Michael Homischer               
|                               |  |                                        | 
|Title:                         |  | Team Leader Large Clients              |  |  |  | Deputy Team Leader Large Clients
|                               |  |                                       
|Constellium Valais S.A. Sierre |  |                                        |  | 
|                               |  |                                        | 
|                               |  | LOGO                                   |  |  |  |                                 
|                               |  |                                        |  |  |  |                                 
|                               |  |                                        | 
|Signed by:                     |  | MARK KIRKLAND                          |  |  |  |                                 
|                               |  |                                        | 
|Title:                         |  | GROUP TREASURER & AUTHORIZED SIGNATORY |  |  |  |