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                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

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                                    FORM 6-K

                        REPORT OF FOREIGN PRIVATE ISSUER

                    Pursuant to Rule 13a-16 or 15d-16 of the
                         Securities Exchange Act of 1934

                         For the month of February, 2007

                        Commission File Number: 000-21742

                                   Acergy S.A.
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                 (Translation of registrant's name into English)

                             c/o Acergy M.S. Limited
                                  Dolphin House
                                  Windmill Road
                                Sunbury-on-Thames
                          Middlesex, TW16 7HT, England
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                    (Address of principal executive offices)

     Indicate by check mark whether the registrant files or will file annual
reports under cover Form 20-F or Form 40-F.

                    Form 20-F [X]              Form 40-F [ ]

     Indicate by check mark if the registrant is submitting the Form 6-K in
paper as permitted by Regulation S-T Rule 101(b)(1): [ ]

     Indicate by check mark if the registrant is submitting the Form 6-K in
paper as permitted by Regulation S-T Rule 101(b)(7): [ ]

     Indicate by check mark whether by furnishing the information contained in
this Form, the registrant is also thereby furnishing the information to the
Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

                    Yes [ ]                    No [X]

     If "Yes" is marked, indicate below the file number assigned to the
registrant in connection with Rule 12g3-2(b): 82-________

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Attached herewith as Exhibit 99.1 is a press release, dated February 21, 2007,
whereby Acergy S.A. (the "Company") announced that it has purchased an
additional 27,600 of its common shares at an average price of NOK 115.25 per
share.

The attached press release shall be deemed to be incorporated by reference into
the prospectuses forming a part of the Company's Registration Statements on Form
S-8 (No. 33-85168, No. 333-9292, No. 333-74321, No. 333-124983 and No.
333-124997) and the Company's Registration Statements on Form F-3 and Form F-3/A
(No. 333-86288) and to be a part of such prospectuses from the date of the
filing thereof.

Certain statements set forth above and contained in the press release furnished
pursuant to this Form 6-K may include "forward-looking statements" within the
meaning of Section 27A of the Securities Act of 1933 and Section 21E of the
Securities Exchange Act of 1934. These statements may be identified by the use
of words like "anticipate," "believe," "estimate," "expect," "intend," "may,"
"plan," "project," "will," "should," "seek," and similar expressions. The
forward-looking statements reflect the Company's current views and assumptions
and are subject to risks and uncertainties. The following factors, and others
which are discussed in the Company's public filings and submissions with the
U.S. Securities and Exchange Commission, are among those that may cause actual
and future results and trends to differ materially from the Company's
forward-looking statements: the general economic conditions and competition in
the markets and businesses in which the Company operates; the Company's
relationship with significant clients; the outcome of legal proceedings or
governmental inquiries; uncertainties inherent in operating internationally; the
impact of laws and regulations; and operating hazards, including spills and
environmental damage. Many of these factors are beyond the Company's ability to
control or predict. Given these factors, you should not place undue reliance on
the forward-looking statements.
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                                    SIGNATURE

          Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by
the undersigned, thereunto duly authorized.


                                               ACERGY S.A.


Date: February 22, 2007                        By: /s/ Johan Rasmussen
                                                  ------------------------------
                                                  Name:  Johan Rasmussen
                                                  Title: VP & General Counsel