The Firm
About us
GS Legal Consulting was created in 2016 with the name Spanish Lawyer NYC, and is the first law firm dedicated to assisting both U.S. citizens residing in Spain and Spanish nationals living in the United States with all matters related to Spanish law.
In addition, our firm advises foreign clients of other nationalities in their relocation to Spain.
Focused on providing legal and tax advice to individuals and small and medium-sized businesses, GS Legal Consulting provides its clients with a tailor-made legal service.
From the Madrid office, we provide service to all our clients through the use of appropriate technological means.
The team
Federico González Seijo
Federico is an attorney admitted in Spain with more than 20 years of professional experience. He is trained at universities in Madrid and New York. He specializes in tax, private wealth, commercial and real estate law.
He holds a JD from Universidad Pontificia de Comillas (ICADE), an LL.M. in Business Law at IE Business School. He also holds an LL.M. in US LAW at Fordham University School of Law (New York).
Sebastián Durán
Sebastián Durán is an attorney admitted in Spain. He joined the Firm in 2024 and is specialized in national and international taxation.
He holds a Law degree from the University of Navarra, along with a diploma in Anglo-American Law. Additionally, he holds an LL.M. in Taxation from CEU San Pablo University in Madrid.
Mary Paz Villalobos
Mary Paz Villalobos joined the Firm in 2025 and is specialized in national and international taxation.
She holds a Law degree from the University of Costa Rica, along with a diploma in International Taxation from the University of Costa Rica. Additionally, she holds an LL.M. in Taxation from Universidad Carlos III de Madrid.
Ariadna Cerezo
Ariadna Cerezo is a paralegal with professional experience in Spain.
She joined the Firm in 2025 and is completing her Law degree at Universidad Carlos III de Madrid, focusing on developing her career in the field of taxation. She will pursue a Master’s degree in Tax Law at Universidad Carlos III de Madrid.
Luis Denuble
Luis is an US attorney admitted in the State of New York, and also in the City of Buenos Aires and federal courts in Argentina. He specializes in advising both Spaniards and Latin Americans who wish to set up a business or incorporate a company in the United States.
He collaborates with Spanish Lawyer NYC through his US firm, Denuble Law PLLC registered in New York and which has an extensive network of associated lawyers.
Nicholas Roscher
Nicholas is a licensed US tax professional. He worked in the international tax space in New York at some of the largest accounting firms in the world. He moved to Madrid in 2015, where he currently resides.
Nicholas collaborates with Spanish Lawyer NYC through his firm, Revolve Tax. Our collaboration provides US taxpayers living in Spain with the perfect coordination on compliance issues in both countries and ensures the reduction or elimination of double taxation whenever possible.
Teresa Vilaseca
Teresa Vilaseca specializes in preparing tax returns for US citizens living abroad. She has been preparing individual US federal and state tax returns since 2024 and moved to Valencia in 2025.
Teresa has a thorough understanding of the foreign tax matters that can affect a US tax return and collaborates with us to alleviate double taxation whenever possible. You can find her at TLV Expat Tax Services.
