Elysium Legal
2 lawyers · Montréal, City of Ottawa, City of Toronto
One of 656 law firms listed in Montréal, and one of 70 handling Tax Law.
Free consultation
Free consultationAbout Elysium Legal
Elysium Legal is a small bilingual litigation firm focused on public and business law, founded by Guillaume Sirois, who's licensed to practise law in both Ontario and Quebec. The firm is based in Montreal, with appointment-only offices in Ottawa and Toronto that let it meet with clients in both provinces in English and French. Before starting the firm, Sirois worked in public law, including time spent defending governments in court and investigating them, and has taken all levels of government to court across the country.
The practice splits its work into two streams. For businesses, it handles tax defence against the Canada Revenue Agency and Revenu Quebec, business formation and regulatory compliance, and administrative defence before regulators. For individuals, organizations, and communities, it takes on Charter and human rights matters, environmental and land use disputes, and public interest litigation, much of it through judicial review of government decisions. The firm says it offers free initial consultations and works on fixed fees or block fee arrangements for defined stages of a file, rather than open ended hourly billing.
Practice areas
In the community
- The firm keeps a blog on its site covering public law developments, including a piece on Quebec's own attempt to halt its electoral boundary redistricting process through legislation and the Supreme Court of Canada's later ruling that the legislation was unconstitutional.
- Other posts walk through how judicial review works in Canada, Charter litigation over rights such as freedom of expression and association, and how to respond to a government investigation or regulatory enforcement action.
Fees & payment
Flat fee
Free consultationLawyers 2
This firm’s lawyers at a glance
- Called to the bar
- 2020–2024 · median 4 years in practice 2 of 2 lawyers
- Law schools
- Université de Montréal, Université de Sherbrooke 2 of 2 lawyers
- Languages on the roster
- English, French
Offices 3
The neighbourhood
Elysium Legal's head office is in Montreal, and the Toronto location is a satellite: an appointment-only office at 197 Yonge Street, Suite 201. The firm uses it to meet Ontario clients in person for matters such as judicial review of municipal or provincial decisions, human rights complaints, and tax disputes with the CRA, work that's handled by the same Montreal-based team rather than a dedicated local branch.
Frequently asked questions
- Is Elysium Legal based in Toronto?
- No. Elysium Legal is based in Montreal. It keeps an appointment-only office at 197 Yonge Street in Toronto so it can meet with Ontario clients, along with a similar office in Ottawa.
- Can Elysium Legal help if the Canada Revenue Agency is auditing my business?
- Yes. The firm handles tax defence at every stage, from responding to an audit notice or CRA information request through to notices of objection, settlement negotiations, and proceedings before the Tax Court of Canada.
- Does Elysium Legal take on Charter or human rights cases?
- Yes. The firm represents individuals and organizations in Charter challenges involving freedom of expression, association, religion, equality rights, and other constitutional matters, as well as discrimination claims.
- Can Elysium Legal challenge a municipal planning or environmental approval?
- Yes. Its environmental and land use practice includes judicial review of environmental approvals and municipal planning decisions, and it can seek injunctions to try to halt development that poses environmental or community harm.
- Does Elysium Legal offer services in French?
- Yes. The firm is fully bilingual, and its founder, Guillaume Sirois, is licensed to practise in both Ontario and Quebec.
- How does Elysium Legal charge for its services?
- The firm offers a free initial consultation and says it works on fixed fees or block fee arrangements for defined stages of a matter, rather than open ended hourly billing.
Similar firms in Montréal
Alepin Gauthier is a family-run law firm based in Laval, Quebec, founded in 1978 by François Alepin. It has grown to more than 120 team members across four Quebec offices (Laval, Vieux-Montréal, downtown Montreal, and…
Business & Corporate Law
Family Law
Bankruptcy & Insolvency
Civil Litigation & Dispute ResolutionAstell & Associés is a boutique law firm in Old Montreal serving both national and international clients. The firm practises in business and corporate law, civil and commercial litigation, agricultural law, real estat…
Business & Corporate LawCivil Litigation & Dispute Resolution
Agricultural LawBankruptcy & Insolvency
Lacy Naster LLP is a Toronto litigation boutique founded by Michael Lacy and Jay Naster. The firm practices in administrative, regulatory, securities, competition, and criminal law, and its lawyers are regularly retai…
Criminal Defence
Administrative & Regulatory LawBusiness & Corporate Law
Tax LawListing compiled from the firm’s public website in August 2026. Verify licence status in the Barreau du Québec directory ↗