<PAGE>

                                                                   Exhibit 10.6

                              COMPLETEL EUROPE N.V.

                      NON-QUALIFIED STOCK OPTION AGREEMENT

     THIS AGREEMENT made as of this 14th day of March, 2001, between
CompleTel Europe N.V., a Netherlands corporation (the "Company"), and Timothy
A. Samples (the "Option Holder").

                                    RECITALS

     A.     The Option Holder is employed by CableTel Management, Inc., a
Colorado corporation ("CableTel"), pursuant to an Employment Agreement dated
as of February 26, 2001, as such agreement may be amended from time to time
(the "Employment Agreement"). CableTel is a wholly-owned subsidiary of
CompleTel LLC.

     B.     CableTel provides management and consulting personnel to the
Company and its subsidiaries. References in this Agreement to the "Company"
shall include the Company's subsidiaries. In connection with his employment
by CableTel, CableTel has seconded the Option Holder to CompleTel
Headquarters UK Ltd. ("CompleTel UK"), a wholly -owned subsidiary of the
Company, to serve as Managing Director and Chief Executive Officer of the
Company under the terms and conditions of the Employment Agreement and a
Secondment Agreement among CableTel, the Option Holder, and CompleTel UK.

     C.     In consideration of the Option Holder's performance of services
for the Company, the Company has determined that it is in the best interests
of the Company to grant the Option Holder an option to purchase ordinary
shares of the Company on the terms and conditions set forth below.

                           NON-QUALIFIED STOCK OPTION

     1.     GRANT OF OPTION. Subject to the terms and conditions of this
Agreement, the Company hereby grants to the Option Holder an option (the
"Option") to purchase an aggregate of 1,500,000 ordinary shares (E.10 nominal
value) of the Company (the "Stock") at an exercise price per share determined
as described in paragraph 2 (the "Option Price"). The Option is granted under
the CompleTel 2000 Stock Option Plan as amended December 20, 2000 (the
"Plan") and shall be governed by the terms of the Plan to the extent not
provided otherwise in this Agreement. If there is any inconsistency between
the terms of this Agreement and the Plan, the terms of this Agreement shall
control.

     2.     REQUIREMENTS FOR EXERCISE; VESTING.

            (a)  IN GENERAL. Except as otherwise provided herein, the Option
shall be granted and become vested and be exercisable as provided in this
Section 2.

<PAGE>

            (b)  GRANT. On March 14, 2001, the Company granted to Option
Holder an Option to acquire an aggregate of 1,500,000 shares of Stock. The
number of shares of Stock shall not be adjusted for any subsequent stock
issuances or dilutive event except as provided in Section 4.

            (c)  PRICE. The price per share shall be E3.94.

            (d)  VESTING. The Option will vest in increments of 375,000
shares on each of the first four anniversaries of the Effective Date if the
Option Holder is still in the employ of the Company on such dates.

            (e)  VESTING IS CUMULATIVE. Except as set forth in Section 5
hereof, the Option shall not be exercisable as to any shares of Stock as to
which the vesting requirements of this Section 2 shall not be satisfied,
regardless of the circumstances under which the Option Holder's employment by
the Company shall be terminated. The number of shares of Stock as to which
the Option may be exercised shall be cumulative, so that once the Option
shall become vested and exercisable as to any shares of Stock it shall
continue to be vested and exercisable as to such shares until expiration or
termination of the Option as provided in Section 6 hereof. If at any time the
number of shares of Stock that are covered by the vested and exercisable
portion of the Option includes a fractional share, the number of shares of
Stock as to which the Option shall be actually vested and exercisable shall
be rounded down to the next whole share of Stock.

     3.     METHOD FOR EXERCISING THE OPTION. The Option may be exercised
only by delivery of written notice of exercise, together with payment of the
Option Price as provided below, in person or through certified or registered
mail, fax or overnight delivery to the Company at the following address:
CompleTel Europe N.V., Attention: Chief Financial Officer, Tour Egee, 9-11
allee de L'Arche; 92671 Courbevoie, Cedex, France, or such other address as
shall be furnished in writing to the Option Holder by the Company. Such
written notice shall specify that the Option is being exercised, and the
number of shares of Stock with respect to which the Option is exercised, and
shall be accompanied by payment of the Option Price.

            The Company may require the Option Holder, as a condition of
exercise of this Option, to give written assurance in substance and form
satisfactory to the Company and its counsel to the effect that the Option
Holder is acquiring the Stock for his own account for investment and not with
any present intention of selling or otherwise distributing the same, and to
such other effects as the Company deems necessary or appropriate in order to
comply with applicable securities laws. Legends evidencing such restrictions
may be placed on the Stock certificates.

            The issuance or transfer of such Stock shall take place at the
address of the Company set forth above upon delivery of the notice of
exercise, at which time the Option Price for the Stock shall be paid in full
in lawful currency (i) by certified or cashier's check payable to the
Company's order, or (ii) by wire transfer to such account as

<PAGE>

may be specified by the Company for this purpose, or (iii) at the election of
the Employee and subject to acceptance of the Company, by selling and
transferring to the Company a number of shares of Stock then owned by the
Option Holder the Fair Market Value of which equals the Option Price of the
Stock to be purchased pursuant to the Option; provided, however, that no
Option may be exercised by sale to the Company of such Stock, unless such
Stock has been held by the Option Holder for more than six (6) months and
provided the Company is able by applicable Dutch law to purchase such Stock.
For purposes of this Option, the Fair Market Value of any shares of Stock
delivered pursuant to (iii) hereof shall be the Fair Market Value as of the
exercise date; the exercise date shall be the day of delivery of the
certificates for the Stock used pursuant to (iii) hereof.

            Upon such notice to the Company and payment of the Option Price,
the exercise of the Option shall be deemed to be effective, and a properly
executed certificate or certificates representing the Stock so purchased
shall be issued by the Company and delivered to the Option Holder; provided
however, the Company shall be under no obligation to issue a certificate or
certificates representing the Stock so purchased until the Option Holder has
made arrangements satisfactory to the Company for the payment of any
withholding or other taxes that arise or become payable as a result of the
exercise of the Option.

            For purposes of this Agreement, Fair Market Value shall mean the
average of the closing prices of the Stock on the PREMIER MARCHE of the PARIS
BOURSE SBF SA for the thirty (30) consecutive trading days prior to the date
on which fair market value is determined.

     4.     ADJUSTMENT OF THE OPTION. The number of shares subject to the
Option and the Option Price shall be adjusted according to Section 4.2 of the
Plan, as such Section is modified by Appendix C to the Plan.

     5.     ACCELERATION OF VESTING

            (a)  ACCELERATION OF VESTING UPON CHANGE IN CONTROL. Upon a
Change in Control of the Company (as defined below) all 1,500,000 Option's
shall become fully vested without regard to the provisions of Section 2
above. Following a Change in Control of the Company, the Option may be
exercised as provided in the Plan.

            A "Change in Control" will be deemed to have occurred if (i) an
individual, entity or group, as defined by Section 13(d)(3) or Section
14(d)(2) of the Securities Exchange Act of 1934 (the "Exchange Act"), that
does not now beneficially own at least ten percent (10%) of the Company's
shares, acquires beneficially more than fifty percent (50%) of the
outstanding shares of the Company; (ii) a merger, acquisition or sale of all
or substantially all of the assets of the Company occurs, in which existing
beneficial shareholders of the Company do not beneficially own at least fifty
percent (50%) of the surviving, successor or acquiring company's common
equity, or (iii) the incumbent

<PAGE>

Supervisory Board of the Company ceases to constitute a majority of the
Company's Board, except for directors elected or approved by the incumbent
board or its successors.

     (b) ACCELERATION OF VESTING UPON TERMINATION WITHOUT CAUSE (AS DEFINED IN
         THE EMPLOYMENT AGREEMENT DATED AS OF 26 FEBRUARY 2001).

     A termination without cause shall occur if the Company delivers a notice
of termination without cause to the Option Holder.

     The Company may terminate Option Holder's employment without cause by
delivering to Option Holder written notice of termination. If Option Holder
is discharged without cause before the first anniversary of the Effective
Date, the Option Holder shall be entitled to receive two full years of
vesting and the options shall be exercisable for two years following such
date of termination. After the first anniversary date and until the third
anniversary date, if Option Holder is discharged for termination without
cause, Option Holder shall be entitled to receive one additional year of
vesting and the options shall be exercisable for two years following such
date of termination.

     6.     EXPIRATION AND TERMINATION OF THE OPTION. The Option shall expire
on the tenth (10th) anniversary of the Effective Date, (the period from the
Effective Date to the expiration date is the "Option Period") or prior to
such time as follows:

            (a)  TERMINATION FOR CAUSE. If the employment of the Option
Holder by the Company is terminated for "cause," within the Option Period,
the unvested portion of the Option shall become void, shall be forfeited and
shall terminate immediately upon the termination of employment of the Option
Holder. The portion of the Option that vested prior to the termination of
employment may be exercised within thirty (30) days of termination and not
thereafter. Any one or more of the following events shall constitute "cause":
(i) conviction of (or pleading NOLO CONTENDERE or equivalent) to a felony or
serious misdemeanor or the equivalent under the laws of another jurisdiction;
(ii) the Option Holder's willful misconduct, gross negligence, or
perpetration of or participation in a fraud or the equivalent under the laws
of another jurisdiction, where such acts are materially injurious to the
Company; (iii) the Option Holder's material breach of the provisions of the
Employment Agreement relating to confidentiality, noncompetition,
nonsolicitation, or the Company's Foreign Corrupt Practices Act policy; or
(iv) the Option Holder's continuous nonfeasance with regard to the Option
Holder's duties, after notice, an opportunity for the Option Holder to appear
before the Company's Supervisory Board, and a reasonable opportunity for the
Option Holder to perform.

            (b)  TERMINATION FOR DISABILITY. If the Option Holder becomes
disabled, the shares subject to the Option that would have vested during the
twelve (12) months following the date of disability, if any, shall vest, and
the Option may be exercised by the Option Holder within one year following
the date of Option Holder's termination on account of disability pursuant to
the Employment Agreement (provided that such exercise must occur within the
Option Period), but not thereafter. In any such case, the Option may be
exercised only as to the shares as to which the Option had

<PAGE>

become exercisable pursuant to this paragraph. For purposes of this Section
6(b), the Option Holder shall be "disabled" if he is unable to effectively
perform the duties required under the Employment Agreement by reason of any
medically determinable physical or mental impairment which can be expected to
result in death within twelve (12) months or which has lasted or can be
expected to last for a continuous period of not less than six (6) months.

            (c)  TERMINATION FOR DEATH. If the Option Holder dies during the
Option Period, the shares subject to the Option that would have vested during
the twelve (12) months following the date of death, if any, shall vest, and
the Option may be exercised by those entitled to do so under the Option
Holder's will or by the laws of descent and distribution within one year
following the Option Holder's death (provided that such exercise must occur
within the Option Period), but not thereafter. In any such case, the Option
may be exercised only as to the shares as to which the Option had become
exercisable pursuant to this paragraph.

            (d)  TERMINATION FOR OTHER REASONS. If the services of the Option
Holder are terminated (which for this purpose means that the Option Holder is
no longer employed by the Company or performing services for the Company)
within the Option Period for any reason other than cause, disability, death,
or by the Option Holder for Good Reason as defined in the Employment
Agreement dated as of 26 February 2001, the Option may be exercised by the
Option Holder within thirty (30) days following the date of such termination
(provided that such exercise must occur within the Option Period), but not
thereafter. In any such case, the Option may be exercised only as to the
shares as to which the Option had become exercisable on or before the date of
termination of services.

            (e)  FORFEITURE OF UNEXERCISED OPTIONS IN CERTAIN CIRCUMSTANCES.
Notwithstanding the foregoing provisions of this Section 6, if, at any time
within the term of this Option, the Option Holder engages in any activity in
competition with any activity of the Company, or inimical, contrary, or
harmful to the interests of the Company, including but not limited to: (A)
conduct related to the Option Holder's employment for which either criminal
or civil penalties against the Option Holder may be sought, (B) violation of
Company policies, including, without limitation, the Company's insider
trading policy, (C) accepting employment with or serving as a consultant,
advisor or in any other capacity to an employer that is in competition with
or acting against the interests of the Company, including employing or
recruiting any present, former or future employee of the Company, (D)
disclosing or misusing any confidential information or material concerning
the Company, or (E) participating in a hostile takeover attempt targeting the
Company, then this Option shall become void, shall be forfeited and shall
terminate effective the date on which the Option Holder enters into such
activity, unless terminated sooner by operation of another term or condition
of this Option or the Plan. The provisions of this subsection may be waived
only if the Company determines in its sole discretion that such action is in
the best interests of the Company.

     7.     TRANSFERABILITY.

<PAGE>

            (a)  IN GENERAL. The Option may not be transferred except by will
or pursuant to the laws of descent and distribution or pursuant to subsection
7(b) below, and it shall be exercisable during the Option Holder's life only
by him, or in the event of his disability or incapacity, by his guardian or
legal representative, and after his death, only by those entitled to do so
under his will or the applicable laws of descent and distribution. Except as
specifically provided herein, upon any attempt to transfer, assign, pledge,
hypothecate or otherwise dispose of the Option or any right or privilege
granted hereunder, or upon the levy of any attachment or similar process upon
the rights and privileges herein conferred, the Option and the rights and
privileges hereunder shall become immediately null and void.

            (b)  TRANSFER TO CERTAIN FAMILY MEMBERS. The Option Holder may
transfer the Option to a member of the Option Holder's immediate family, a
trust of which members of the Option Holder's immediate family are the only
beneficiaries, or a partnership of which members of the Option Holder's
immediate family or trusts for the sole benefit of the Option Holder's
immediate family are the only partners (the "InterVivos Transferee").
Immediate family means the Option Holder's spouse, issue (by birth or
adoption), parents, grandparents, siblings (including half brothers and
sisters and adopted siblings) and nieces and nephews. No transfer shall be
effective unless the Option Holder shall have notified the Company of the
transfer in writing and has furnished a copy of the documents that effect the
transfer to the Company. The InterVivos Transferee shall be subject to all of
the terms of this Agreement, including, but not limited to, the vesting
schedule, termination provisions, and the manner in which the Option may be
exercised; provided however, that the InterVivos Transferee may not pay the
Option Price by selling shares to the Company as described in subsection
3(iii). The Company may require the Option Holder and the InterVivos
Transferee to enter into an appropriate agreement with the Company providing
for, among other things, the satisfaction of required tax withholding with
respect to the exercise of the transferred Option and the satisfaction of any
Stock retention requirements applicable to the Option Holder, together with
such other terms and conditions as may be specified by the Company. Except to
the extent provided otherwise in this Agreement, the InterVivos Transferee
shall have all of the rights and obligations of the Option Holder under this
Agreement and the Plan.

     8.     LIMITATION OF RIGHTS. The Option Holder, an InterVivos
Transferee, or his successor shall have no rights as a stockholder with
respect to the shares of Stock covered by this Option until the Option
Holder, an InterVivos Transferee or his successors become the holder of
record of such shares.

     9.     STOCK RESERVE. The Company shall at all times during the term of
this Agreement reserve and keep available such number of shares of Stock as
will be sufficient to satisfy the requirements of this Agreement, and the
Company shall pay all original issue taxes (if any) on the exercise of the
Option, and all other fees and expenses necessarily incurred by the Company
in connection therewith.

<PAGE>

     10.    WITHHOLDING. The issuance of Stock pursuant to the exercise of
this Option shall be subject to the requirement that the Option Holder shall
make appropriate arrangements with the Company to provide for the amount of
additional income and other tax withholding applicable to the exercise of the
Option.

     11.    MISCELLANEOUS.

            (a)  NOTICES. Any notice required or permitted to be given under
this Agreement shall be in writing and shall be given by first class
registered or certified mail, postage prepaid, or by personal delivery to the
appropriate party, addressed :

                 (i)    If to the Company,  to CompleTel Europe N.V., Tour Egee,
     9-11 allee de L'Arche; 92671 Courbevoie, Cedex, France, Attn.: Chief
     Financial Officer or at such other address as may have been furnished to
     the Option Holder in writing by the Company; or

                 (ii)   If to the Option Holder, to the Option Holder at
     59 Frognal, London, NW3 6YA, England, or at other address as may have been
     furnished to the Company by the Option Holder.

Any such notice shall be deemed to have been given as of the second day after
deposit in the United States mails, postage prepaid, properly addressed as
set forth above, in the case of mailed notice, or as of the date delivered in
the case of personal delivery.

            (b)  AMENDMENT.  Except as provided  herein,  this  Agreement may
not be amended or otherwise modified unless evidenced in writing and signed
by the Company and the Option Holder.

            (c)  COMPLIANCE WITH SECURITIES LAWS. This Agreement shall be
subject to the requirement that if at any time counsel to the Company shall
determine that the listing, registration or qualification of the shares of
Stock subject to the Option upon any securities exchange or under any the law
of any state or country, or the consent or approval of any governmental or
regulatory body, is necessary as a condition of, or in connection with, the
issuance or acquisition of such shares thereunder, the Option may not be
exercised in whole or in part unless such listing, registration,
qualification, consent or approval shall have been effected or obtained on
conditions acceptable to the Committee. Nothing herein shall be deemed to
require the Company to apply for or obtain such listing, registration or
qualification.

            (d)  CONSTRUCTION; SEVERABILITY. The section headings contained
herein are for reference purposes only and shall not in any way affect the
meaning or interpretation of this Agreement. The invalidity or
unenforceability of any provision of this Agreement shall not affect the
validity or enforceability of any other provision of this Agreement, and each
other provision of this Agreement shall be severable and enforceable to the
extent permitted by law.

<PAGE>

            (e)  WAIVER. Any provision contained in this Agreement may be
waived, either generally or in any particular instance, by the Committee
appointed under the Plan, but only to the extent permitted under the Plan.

            (f)  BINDING EFFECT. This Agreement shall be binding upon and
inure to the benefit of the Company and the Option Holder and their
respective heirs, executors, administrators, legal representatives,
successors and assigns.

            (g)  RIGHTS TO EMPLOYMENT. Nothing contained in this Agreement
shall be construed as giving the Option Holder any right to be retained in
the employ of the Company or any parent, subsidiary or affiliate of the
Company and this Agreement is limited solely to governing the rights and
obligations of the Option Holder with respect to the Stock and the Option.

            (h)  GOVERNING LAW. This Agreement shall be governed by and
construed in accordance with the laws of the State of Colorado, United
States, subject to any United Kingdom labor law provisions that may apply in
the case of an employee seconded to the United Kingdom by an employer not
established in the United Kingdom.

     IN WITNESS WHEREOF, the parties have executed this Agreement as of the
day and year first above written.

                                        COMPLETEL EUROPE N.V.

                                        By
                                        ---------------------------------------


                                        OPTION HOLDER


                                        ---------------------------------------
                                        Timothy A. Samples