3 1 form-3.txt U.S. SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 3 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(f) of the Investment Company Act of 1940 ________________________________________________________________________________ 1. Name and Address of Reporting Person* Cadim Inc. -------------------------------------------------------------------------------- (Last) (First) (Middle) 800, Square Victoria, Bureau 4400, Case postale 118 -------------------------------------------------------------------------------- (Street) Montreal, Quebec H4Z 1B7 -------------------------------------------------------------------------------- (City) (State) (Zip) ________________________________________________________________________________ 2. Date of Event Requiring Statement (Month/Day/Year) August 22, 2001 ________________________________________________________________________________ 3. IRS Identification Number of Reporting Person, if an Entity (Voluntary) ________________________________________________________________________________ 4. Issuer Name and Ticker or Trading Symbol Prime Group Realty Trust (NYSE: PGE) ________________________________________________________________________________ 5. Relationship of Reporting Person to Issuer (Check all applicable) [_] Director [x] 10% Owner [_] Officer (give title below) [_] Other (specify below) ________________________________________________________________________________ 6. If Amendment, Date of Original (Month/Day/Year) ________________________________________________________________________________ 7. Individual or Joint/Group Filing (Check applicable line) [x] Form Filed by One Reporting Person [_] Form Filed by More than One Reporting Person ================================================================================ Table I -- Non-Derivative Securities Beneficially Owned ================================================================================

* If the Form is filed by more than one Reporting Person, see Instruction 5(b)(v). Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. (Print of Type Responses) (Over) FORM 3 (continued) Table II -- Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities) ================================================================================

/s/ Richard Dansereau September 4, 2001 ----------------------------------------- -------------------------- **Signature of Reporting Person Date ** 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 provided is insufficient, see Instruction 6 for procedure. (Print of Type Responses) Page 2

CADIM INC 3