A Quebec civil union agreement (convention d'union civile) is a legally binding contract between two partners who intend to enter into a civil union under the Code civil du Québec (C.c.Q.), specifically articles 521.1 through 521.19. The civil union (union civile) is a legal institution unique to Quebec, created by the Quebec National Assembly in 2002 through An Act instituting civil unions and establishing new rules of filiation. It was originally designed to provide same-sex couples with a formal legal framework for their relationships before the legalization of same-sex marriage in Canada in 2005, but it remains available to both same-sex and opposite-sex couples as a distinct alternative to marriage.

Under article 521.1 C.c.Q., a civil union is defined as the commitment by two persons aged eighteen or older who express their free and enlightened consent to live together and to respect the rights and obligations that flow from that status. Unlike a common law relationship (union de fait), which exists simply by virtue of cohabitation and creates limited legal obligations, a civil union must be formally celebrated before an authorized officiant and creates comprehensive legal rights and obligations between the partners.

Article 521.6 C.c.Q. establishes a fundamental principle: partners in a civil union have, during the union, the same rights and the same obligations as married spouses. This means that all the rules governing marriage in the Code civil du Québec apply to civil unions with the necessary adaptations. These include the mutual obligations of respect, fidelity, assistance, and support (by reference to art. 392 C.c.Q.), the contribution to household expenses proportional to respective means (by reference to art. 396 C.c.Q.), the family residence protections (arts. 401-413 C.c.Q.), and the mandatory family patrimony rules (arts. 414-426 C.c.Q.).

The patrimonial regime governs the financial relationship between the partners during the union. Under article 521.8 C.c.Q., partners who have not signed a civil union contract before a notary prior to the celebration are automatically subject to the default regime of partnership of acquests (société d'acquêts), governed by articles 432-492 C.c.Q. Under this regime, property acquired during the union is classified as acquests and is shared equally upon dissolution, while property owned before the union or received by gift or inheritance remains the exclusive property of each partner. Alternatively, the partners may choose separation as to property (séparation de biens) by entering into a notarial contract before the celebration of the union.

Regardless of the patrimonial regime chosen, the family patrimony rules (arts. 414-426 C.c.Q.) apply mandatorily to all civil unions. These rules are of public order (d'ordre public) under article 423 C.c.Q. and cannot be waived by agreement. The family patrimony includes: the family residences used by the partners, the furniture that serves for the use of the household and ornaments the residences, the motor vehicles used for family travel, and the rights accumulated during the union under a retirement plan. Upon dissolution of the civil union, the value of the family patrimony is divided equally between the partners, regardless of which partner owns the property.

One of the most distinctive features of the civil union is the simplified dissolution mechanism. Under article 521.12 C.c.Q., a civil union may be dissolved by the death of one partner, by a judgment of the court, or by a joint notarial declaration. The joint notarial declaration (art. 521.13 C.c.Q.) allows both partners to dissolve their union by appearing before a notary and making a joint declaration accompanied by a notarial agreement settling all the consequences of the dissolution, including the division of the family patrimony, liquidation of the patrimonial regime, support obligations, and arrangements for any children. This notarial dissolution process is not available for marriages, which can only be dissolved by judicial divorce, making the civil union administratively simpler to end when both parties agree.

The civil union agreement (also called a civil union contract) plays a crucial role in defining the financial relationship between the partners. When partners wish to choose a patrimonial regime other than the default partnership of acquests, or when they wish to include specific provisions regarding their financial arrangements, donations between partners, or other matters, they must enter into a written contract received before a notary prior to the celebration of the civil union.

When two persons in Quebec wish to formalize their relationship through a civil union and want to specify their patrimonial regime, particularly if they prefer separation as to property (séparation de biens) over the default partnership of acquests (société d'acquêts).

When partners entering a civil union want to document their existing assets at the time of the union, which is important for determining what constitutes separate property versus acquests under the partnership of acquests regime, or for establishing the baseline value of assets subject to family patrimony division.

When couples who have been living in a common law relationship (union de fait) wish to formalize their status and gain the legal protections of a civil union, including the mandatory family patrimony rules, family residence protections, and mutual obligations of support and assistance.

When partners want to include specific provisions regarding their financial contributions to household expenses, donations between partners, or other arrangements permitted by the Code civil du Québec.

When same-sex or opposite-sex couples prefer a civil union over marriage because they want to maintain the option of simplified notarial dissolution if the relationship ends, rather than being required to go through judicial divorce proceedings.

Patrimonial Regime Selection -- The agreement must specify whether the partners choose the partnership of acquests (société d'acquêts, the default under CCQ art. 521.8) or separation as to property (séparation de biens). If no contract is signed, the partnership of acquests applies automatically. The choice of regime affects how property is owned and divided upon dissolution of the union.

Family Patrimony Declaration -- Under CCQ arts. 414-426, applied to civil unions by art. 521.6, the family patrimony rules are mandatory and cannot be waived. The agreement should document the partners' existing assets at the time of the union to establish clear baselines for future patrimony division.

Family Residence -- The agreement should identify the intended family residence. Under CCQ arts. 401-413, the family residence receives special protection: the owner-partner cannot sell, mortgage, or encumber it without the other partner's written consent, regardless of the patrimonial regime.

Effects of the Civil Union -- Under CCQ art. 521.6, partners have the same rights and obligations as married spouses: mutual respect, fidelity, assistance, and support; contribution to household expenses; and shared direction of the family.

Dissolution Provisions -- The agreement should address how the civil union may be dissolved: by death, court judgment, or joint notarial declaration (art. 521.12-521.13 CCQ). The simplified notarial dissolution is a distinctive feature of the civil union institution.

Good Faith (Bonne Foi) -- Article 1375 C.c.Q. requires that all obligations be performed in good faith, governing the conduct of both partners throughout the union and in its dissolution.

Notarization -- A civil union contract must be received before a notary (art. 521.8 CCQ). Without notarization, the contract is not valid and the default regime applies.