Onur Sümer

Firm-published professional — credential not independently checked

Attorney at Law, Managing Partner at GSC International

Onur Sümer is listed on the İstanbul Barosu Baro Levhası as Avukat, sicil 87336, Büro Şişli, phone matching GSC International’s Istanbul office. Admitted year not published on the public Levha grid.

What is on file: Firm-published identity and role. No current official credential check.
Record reviewed: 10 Sept 2026

Enquiries are handled by GSC International, not directly by Onur.

Directory listing. We reviewed this firm-published professional record on 10 Sept 2026, but no current official credential check is on file for Onur. How we verify

What Onur does

Jurisdictions: Portugal, Greece, MaltaFirm level
Works in: Spanish, French, Italian, English, Turkish
Relationship to the firm: Partner

Routes Onur handlesFirm level

Track record

20: Years in practiceStated by the firm

Credentials

Education

Law studies

Université Paris 1 Panthéon-Sorbonne
Law (exact title unpublished)

Istanbul University

Working with Onur

Enquiries: Handled by GSC InternationalFirm level
First consultation: Not stated
Typical engagement fee: Not stated
Typical first reply: Not stated
Languages of engagement: Spanish, French, Italian, English, Turkish

Common questions

What is Onur Sümer’s role at GSC International?

He is the firm’s managing partner and an attorney. GSC International presents him as a senior cross-border adviser working across its international office network.

Is Onur Sümer admitted to a bar association?

GSC International identifies him as an attorney registered with the Istanbul Bar Association. This is firm-published information; an independent regulator-directory match was not located during verification.

Where did Onur Sümer study law?

GSC International says he studied law at Paris 1 Panthéon-Sorbonne University and Istanbul University. The biography does not publish graduation years or the exact award titles.

What legal work does Onur Sümer handle?

His firm biography describes work in corporate, commercial, international and banking law, including cross-border advisory matters in Europe and the United Arab Emirates.

What languages does Onur Sümer speak, and does he hold a diplomatic role?

GSC International’s biography says he is fluent in Turkish, French, English, Italian and Spanish. It also says he has served as Honorary Consul of the Slovak Republic in Türkiye since 2016.

This record

On file: Firm-published identity and relationship. No current official credential check is on file.
Record reviewed: 10 Sept 2026
Next review: 10 Sept 2027
Credential status: This person is shown from firm-published material and has not passed GVL's official credential check.
Not checked: Figures stated by the firm, which we publish with their source but do not independently confirm.

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