<PAGE>   1
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM 10-Q

(Mark One)

[X]      QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
         EXCHANGE ACT OF 1934 For the period ended March 31, 2000

                                       or

[ ]      TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
         EXCHANGE ACT OF 1934 For the Transition period from _________________
         to ________________ Commission File Number 33-16973



                                   NET 1 L.P.
             (Exact name of Registrant as specified in its charter)

<TABLE>
<S>                                                         <C>
                  Delaware                                      13-3421566
       (State or other jurisdiction of                       (I.R.S. Employer
       incorporation or organization)                       Identification No.)

  c/o Lexington Corporate Properties Trust
            355 Lexington Avenue
                New York,  NY                                      10017
(Address of principal executive offices)                        (Zip Code)
</TABLE>

Registrant's telephone number, including area code          (212) 692-7200

Securities registered pursuant to Section 12(b) of the Act: None

Securities registered pursuant to Section 12(g) of the Act: Units of Limited
Partnership Interests

Indicate by check mark whether the Registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the Registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.

                                  Yes x      No

State the aggregate market value of the voting stock held by non-affiliates of
the Registrant.
                                Not applicable.

There is no active public market for the units of limited partnership interests
issued by the Registrant.
<PAGE>   2
                         PART 1. - FINANCIAL INFORMATION
                          ITEM 1. FINANCIAL STATEMENTS

                    NET 1 L.P. AND CONSOLIDATED PARTNERSHIPS

                           CONSOLIDATED BALANCE SHEETS
            (Dollars in thousands, except units and per unit amounts)

                March 31, 2000 (unaudited) and December 31, 1999

<TABLE>
<CAPTION>
                                                              March 31,          December 31,
                            Assets                              2000                 1999
                                                              --------             --------
<S>                                                           <C>                  <C>
Real estate, at cost                                          $ 38,711             $ 38,711
     Less: accumulated depreciation                              2,683                2,483
                                                              --------             --------
                                                                36,028               36,228

Cash and cash equivalents                                        1,839                1,951
Restricted cash                                                  1,723                1,710
Rent receivable                                                  1,032                  504
Other assets                                                       376                  528
                                                              --------             --------
                                                              $ 40,998             $ 40,921
                                                              ========             ========



               Liabilities and Partners' Capital

Long term debt                                                $ 16,114             $ 16,272
Accrued interest payable                                           111                   88
Accounts payable and other liabilities                             674                  912
                                                              --------             --------
                                                                16,899               17,272
                                                              --------             --------
Partners' capital (deficit):
General Partner                                                    (88)                 (96)
Limited Partners ($1,000 per Unit, 50,000 Units
  authorized, 30,772 Units issued and outstanding)              24,187               23,745
                                                              --------             --------
     Total partners' capital                                    24,099               23,649
                                                              --------             --------

                                                              $ 40,998             $ 40,921
                                                              ========             ========
</TABLE>

See accompanying notes to unaudited consolidated financial statements.
<PAGE>   3
                    NET 1 L.P. AND CONSOLIDATED PARTNERSHIPS

                        CONSOLIDATED STATEMENTS OF INCOME
                 (Dollars in thousands, except per Unit amounts)

                   Three Months Ended March 31, 2000 and 1999
                                   (Unaudited)

<TABLE>
<CAPTION>
                                                    2000              1999
                                                   ------            ------
<S>                                                <C>               <C>
Revenues:
     Rental                                        $1,440            $1,127
     Interest and other                                41                20
                                                   ------            ------
                                                    1,481             1,147
                                                   ------            ------
Expenses:
     Interest                                         334               122
     Depreciation                                     200               118
     General, administrative, and other               103               119
                                                   ------            ------
                                                      637               359
                                                   ------            ------

Net income                                         $  844            $  788
                                                   ======            ======


Net income per Unit of limited
     partnership interest                          $26.87            $25.10
                                                   ======            ======
</TABLE>

See accompanying notes to unaudited consolidated financial statements.
<PAGE>   4
                    NET 1 L.P. AND CONSOLIDATED PARTNERSHIPS

                 CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
                             (Dollars in thousands)

                   Three Months Ended March 31, 2000 and 1999
                                   (Unaudited)

<TABLE>
<CAPTION>
                                                              2000                1999
                                                             -------             -------
<S>                                                          <C>                 <C>
Net cash provided by operating activities:                   $   453             $   391
                                                             -------             -------

Cash flows from financing activities:
     Increase in restricted cash                                 (13)               --
                                                             -------             -------

Cash flows from financing activities:
     Principal payments on mortgage notes                       (158)                (89)
     Cash distributions to partners                             (394)               (394)
                                                             -------             -------
     Net cash used in financing activities                      (552)               (483)
                                                             -------             -------

Decrease in cash and cash equivalents                           (112)                (92)
Cash and cash equivalents at beginning of period               1,951               1,688
                                                             -------             -------
Cash and cash equivalents at end of period                   $ 1,839             $ 1,596
                                                             -------             -------

Supplemental disclosure of cash flow information:
Cash paid during the period for interest                     $   311             $   122
                                                             =======             =======
</TABLE>

See accompanying notes to unaudited consolidated financial statements.
<PAGE>   5
                    NET 1 L.P. AND CONSOLIDATED PARTNERSHIPS

                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

                                 March 31, 2000
                                   (Unaudited)



1.       The Partnership and Basis of Presentation

         Net 1 L.P. (the "Partnership") was formed as a limited partnership on
         August 25, 1987 under the laws of the State of Delaware to invest in
         net leased real estate properties or interests therein. As of March 31,
         2000, the Partnership had owned interests in eight properties.

         As of March 31, 2000, the Partnership has a total of 30,772 Units
         issued and outstanding held by approximately 1,400 limited partners.

         The unaudited financial statements reflect all adjustments that are, in
         the opinion of the General Partner, necessary to present a fair
         statement of condition and the results for the interim period
         presented. For a more complete understanding of the Partnership's
         financial position and accounting policies, reference is made to the
         financial statements previously filed with the Securities and Exchange
         Commission with the Partnership's Annual Report on Form 10-K for the
         year ended December 31, 1999.

2.       Summary of Significant Accounting Policies

         Net income per Unit amounts were calculated by using the weighted
         average number of Units outstanding for each period and allocating 98%
         of the income attributable for that period to the Limited Partners. The
         weighted average number of Units outstanding was 30,772 for all periods
         presented.

         Management of the Partnership has made a number of estimates and
         assumptions relating to the reporting of assets and liabilities, the
         disclosure of contingent assets and liabilities and the reported
         amounts of revenues and expenses to prepare these financial statements
         in conformity with generally accepted accounting principles.
         Actual results could differ from those estimates.

3.       The Partnership Agreement

         For financial statement reporting purposes all items of income are
         allocated in the same proportion as distributions of distributable
         cash.

         Distributable cash attributed to a particular limited partner's Unit is
         calculated from the date of admission to the Partnership. The unpaid
         cumulative preferred return at March 31, 2000 totaled $15.007 million
         ($484.48 to $490.33 per Unit, per close). On April 28, 2000, the unpaid
         cumulative preferred return was reduced by a cash distribution to the
         Limited Partners totaling $384,958 ($12.51 per Unit). The General
         Partner received a cash distribution of $7,856 on April 28, 2000.
<PAGE>   6
                    NET 1 L.P. AND CONSOLIDATED PARTNERSHIPS

                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS



4.       Related Party Transactions

         Leased Properties Management, Inc., an affiliate of the General
         Partner, is entitled to receive a fee for managing the Partnership's
         properties in the amount of 1% of gross annual rental receipts (or a
         greater amount in certain circumstances). For the three months ended
         March 31, 2000 and 1999, property management fees of $14,000 and
         $11,000 were incurred.

         Lexington Corporate Properties Trust, whose chairman and Co-Chief
         Executive Officer is an officer and a shareholder of the General
         Partner, is reimbursed by the Partnership for various administrative
         services performed. For the three months ended March 31, 2000 and 1999
         such reimbursements totaled $61,000 and $42,000, respectively.
<PAGE>   7
                  ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS
                OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

Liquidity and Capital Resources

The Partnership attempts to maintain a working capital reserve in an amount
equal to 3% of the gross proceeds of its offering, an amount that is anticipated
to be sufficient to satisfy liquidity requirements. Liquidity of the Partnership
could be adversely affected by unanticipated costs, lessees experiencing
financial difficulties and greater than anticipated operating expenses. To the
extent that such working capital reserves are insufficient to satisfy the cost
requirements of the Partnership, additional funds may be obtained through
short-term or permanent loans or by reducing distributions to limited partners.

The unpaid cumulative preferred return at March 31, 2000 totaled $15.007 million
($484.48 to $490.33 per Unit, per close), and was reduced by $384,958 ($12.51
per Unit) with the distribution paid in April 2000.

Except for the debt service requirements under the mortgages, there are no
material restrictions upon the Partnership's present or future ability to make
distributions in accordance with the provisions of its Partnership Agreement.

As of March 31, 2000, the restricted cash represents remaining proceeds from the
sale of properties under the Internal Revenue Code Section 1031, restricted for
investment in future acquisitions.

Impact of Year 2000

To date there have been no situations that the General Partner is aware of,
where the year 2000 issue has caused a computer system that effects the
Partnership or any of its properties to function improperly.

Results of Operations (in thousands):

<TABLE>
<CAPTION>
                                         Three Months Ended
                                              March 31,
                                       ------------------------
                                        2000              1999        Increase (Decrease)
                                       ------            ------            ------
<S>                                    <C>               <C>               <C>
Total revenues                         $1,481            $1,147            $  334
                                       ------            ------            ------
Total expenses:
 Interest                                 334               122               212
 Depreciation                             200               118                82
 General and administrative               103               119               (16)
                                       ------            ------            ------
                                          637               359               278
                                       ------            ------            ------
Net income                             $  844            $  788            $   56
                                       ======            ======            ======
</TABLE>

The change in results of operations with respect to revenues, interest and
depreciation for the three months ended March 31, 2000 are primarily
attributable to the operations of the real property investments acquired in
September 1999.

General and administrative expenses decreased in the three months ended March
31, 2000 due to property appraisals incurred in the first quarter of 1999.
<PAGE>   8
       ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

         There is no exposure to market risk since all of the Partnership's
long-term indebtedness is fixed rate.
<PAGE>   9
                           PART II - OTHER INFORMATION

ITEM 1.  Legal Proceedings - not applicable.

ITEM 2.  Changes in Securities - not applicable.

ITEM 3.  Defaults under the Senior Securities - not applicable.

ITEM 4.  Submission of Matters to a Vote of Security Holders - not applicable.

ITEM 5.  Other Information - not applicable.

ITEM 6.  Exhibits and Reports on Form 8-K.

                  (a)      Exhibits.
                           Exhibit No.                        Exhibit
                           -----------                        -------
                               27                     Financial Data Schedule

                  (b)      Reports on form 8-K filed during the first quarter
                           ended March 31, 2000.

                           Form 8-K/A dated September 27, 1999, filed January
                           14, 2000. Provided certain historical financial
                           information for a property located in Phoenix,
                           Arizona.
<PAGE>   10
                                   SIGNATURES

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.

                                             NET 1 L.P.

                                             By:   Lepercq Net 1 L.P.
                                                   its general partner

                                             By:   Lepercq Net 1 Inc.
                                                   its general partner


Date:    May 15, 2000                        By:   /s/ E. Robert Roskind
         ---------------------                     -----------------------------
                                                   E. Robert Roskind
                                                   President