Executive Summary: Key Legal and Evidentiary Issues

• Extent to which a lawyer may recover additional professional fees when an initial invoice contained a material calculation error on agreed contingency-type fees of 10% of amounts recovered.
• Characterisation of the billing error as a purely material mistake that does not alter the binding effect of the original written fee agreement between lawyer and clients.
• Determination of the applicable three-year extinctive prescription period for claims to unpaid professional fees and identification of the correct starting point for the limitation period.
• Assessment of whether the lawyer’s late discovery of his own billing error could delay, suspend, or interrupt prescription under the Civil Code of Québec.
• Evaluation of client conduct (silence and failure to respond to follow-up letters and a demand notice) and whether this affects the running of prescription.
• Allocation of costs where the lawyer’s claim is dismissed as prescribed, including ordering the lawyer to reimburse the successful defendants their filing fees of 115 $.

Facts of the case

Jean-François Lacoursière, a lawyer, represented Valérie Laroche and Patrick Lefebvre in the well-known “pyrrhotite” litigation, a mass set of construction and property damage claims in Québec. The parties had entered into a written professional fee agreement in May 2012, under which the clients agreed to pay professional fees equal to 10% of the sums recovered at the conclusion of the case. Following a settlement and the receipt of the recovery amounts, Mr. Lacoursière prepared and sent an invoice on 11 August 2020. The amount recovered on behalf of the clients was 71 431,18 $. Under the 10% fee agreement, the lawyer’s fees should have been calculated on the basis of 7 143,12 $ in fees before taxes, with applicable GST and QST added. However, the August 2020 invoice contained an obvious calculation error. The document recited fees of 7 143,12 $, added 5% GST and 9.975% QST, but showed a total of only 4 286,55 $, an amount that is mathematically inconsistent with 7 143,12 $ plus both taxes. After certain deductions were applied, the invoice reflected “honoraires dus” of 3 224,24 $, which the clients paid without raising any question. Neither the lawyer nor the clients noticed the arithmetic error at that stage.

Discovery of the billing error and second invoice

Approximately fourteen months later, on 7 October 2021, Mr. Lacoursière discovered that the August 2020 invoice understated his total fees and taxes. He wrote to Laroche and Lefebvre explaining that an error of calculation had occurred in the first bill. According to his corrected calculation, the total fees after taxes should have been 8 212,81 $, not 4 286,55 $, leaving an unpaid balance of 3 926,26 $. He enclosed a second invoice showing this “solde impayé” as the difference between what should have been billed and what had been previously charged and paid. In his letter, the lawyer apologised for the mistake and proposed that the clients could pay the outstanding balance by way of ten monthly instalments, or alternatively contact him to propose another reasonable arrangement.

Clients’ reaction and further correspondence

The clients did not respond to the 7 October 2021 letter. They neither accepted the proposed instalment plan nor disputed the reasoning behind the recalculated fees. They also remained silent in the face of subsequent reminders sent on 25 November 2021, 19 January 2022, and 19 April 2022. Ultimately, the lawyer sent a formal demand letter on 15 January 2024, which also went unanswered. Throughout this period, the clients did not pay any part of the additional 3 926,26 $ being claimed, and they did not engage in any written or verbal dialogue with their former lawyer about the alleged residual fees.

Commencement of legal proceedings

Frustrated by the lack of response, Mr. Lacoursière initiated proceedings in the Small Claims Division of the Court of Québec on 19 February 2024. His claim sought recovery of the unpaid balance of 3 926,26 $, representing the additional professional fees allegedly owing under the 2012 fee agreement once the calculation error was corrected. In their defence, Laroche and Lefebvre denied owing the amounts claimed, arguing that the billing was unclear and that any calculation error in the original invoice was the sole responsibility of their lawyer, who must assume the consequences. At the hearing, the defendants also raised an additional and decisive argument: that the claim for unpaid fees was prescribed (time-barred) under Québec’s rules on extinctive prescription.

No dispute over the fee agreement or correct calculation

The Court first addressed the nature of the error in the August 2020 invoice and the effect of that error on the parties’ contractual relationship. The written fee agreement clearly provided for payment of fees equal to 10% of the sums recovered, and both parties accepted this as their true agreement. The Court characterised the initial billing mistake as a purely material error of calculation. Such a clerical or arithmetic error does not, in the Court’s view, constitute grounds for annulling or modifying the underlying contract, which reflected the parties’ real intention. On the evidence, the correct total amount of fees after taxes was indeed 8 212,81 $, significantly higher than the 4 286,55 $ reflected in the first invoice. The Court therefore held that, as of 7 October 2021, the lawyer was substantively entitled to claim the unpaid balance of 3 926,26 $, based on the agreed 10% fee and proper application of GST and QST.

Analysis of prescription and starting point of the limitation period

The central legal issue ultimately turned not on the correctness of the fee calculation, but on whether the claim was out of time. Under the Civil Code of Québec, a claim to enforce a personal right—such as a claim for unpaid professional fees—is subject to a three-year extinctive prescription period. That period starts to run from the day on which the right of action arises. In fee disputes, Québec courts generally consider that the right of action arises at the end of the mandate, or upon completion of the work or services, rather than when an error is discovered or a corrected bill is sent. Applying this framework, the Court found that the lawyer’s services had unquestionably come to an end by 11 August 2020, the date of the original invoice. That date therefore marked the starting point of the three-year prescription period. From that point, Mr. Lacoursière had until 11 August 2023 to interrupt prescription by filing a claim in court.

Effect of the late discovery of the error

The Court then examined whether the lawyer’s belated discovery of his own calculation error in October 2021 could delay or suspend the running of prescription. It held that it could not. The mistake and the lawyer’s ignorance of it until October 2021 were circumstances entirely internal to the plaintiff and not attributable to the defendants or to any external cause beyond his control. As such, they did not amount to a case of “impossibility in fact to act” that would suspend prescription under the Civil Code provisions on interruption and suspension. The Court emphasised that the defendants, for their part, learned of the error as of 7 October 2021 and from that moment knew or could not ignore that the lawyer was claiming a higher amount of fees—8 212,81 $ in total, rather than 4 286,55 $. Nonetheless, their silence and failure to respond did not stop prescription from running.

Outcome and cost consequences

In light of these findings, the Court held that the proceeding filed on 19 February 2024 was lodged more than three years after 11 August 2020 and therefore after the expiry of the prescription period. Although the fee agreement entitled Mr. Lacoursière, in principle, to the corrected fee total, his failure to act within the statutory time limit was decisive. The Court accordingly declared the claim prescribed and ordered that the action be dismissed. As a result, the successful parties in this case were the defendants, Valérie Laroche and Patrick Lefebvre, who successfully resisted the late attempt by their former lawyer to recover additional fees. In addition, the Court ordered Mr. Lacoursière to pay them 115 $ in judicial costs corresponding to the filing fees for their contestation, which was the total monetary amount awarded in favour of the successful parties.