Our team of experts

Maibaum Rechtsanwalts GmbH is backed by a team that supports people in residence and migration law with expertise, clarity and empathy.

Björn Maibaum

Mr. Björn Maibaum is a lawyer and specialist lawyer for migration law.

After studying law with a focus on European law and Japanese language in Giessen and Cologne, he worked as a trainee lawyer at the German Chamber of Foreign Trade in Tokyo, at the public prosecutor’s office and the regional court in Wuppertal.

He later worked as a lawyer in an office partnership with the lawyers Christ and Külschbach in Cologne Lindenthal. Since 2004, he has headed the law firm Maibaum in Cologne, specializing in citizenship, migration and immigration law. In 2021, he took over the management of Maibaum Rechtsanwalts GmbH.

Mr. Maibaum is a member of the Working Group on Aliens and Asylum Law at the German Bar Association, a member of the Specialist Bar Association for Migration Law, a member of the German-Japanese Lawyers’ Association (DJJV) and is a member of the preliminary examination committee for the award of the specialist lawyer title for migration law in the Cologne Bar Association district.

Gunter Christ

Gunter Christ studied law at the University of Cologne, was admitted to the bar in 1987 and has practiced in Cologne ever since, specializing in migration law. Mr. Christ is known throughout Germany as a proven specialist for Afghanistan. He has been a member of the Cologne Refugee Council since the late 1980s and a member of a working group for lawyers specializing in immigration and refugee law throughout North Rhine-Westphalia since 1987, which he has organized for many years. Since January 1998, he has also been a legal advisor to the Diocesan Caritas Association for the Archdiocese of Cologne and the German Caritas Association for the area of foreign refugees and, in this capacity, a member of the Legal Advisors’ Conference of Lawyers Working with Welfare Associations and the United Nations High Commissioner for Refugees (RBK). In May 2000, Mr. Christ co-founded the Working Group on Aliens and Asylum Law in the German Bar Association in Berlin and was, among other things, a member of the first managing committee.

Natasha Bond

Ms. Bond studied English and German law at the University of Cologne and University College London. During her studies, she was already very committed to helping refugees, including at the Student Action for Refugees Society in London, where she was a member of the board. She has been a member of the Refugee Law Clinic Cologne since 2019. During her legal clerkship in the Higher Regional Court district of Cologne, she worked for the NGO Transparency International and a law firm for migration law, among others, gaining valuable experience for her work as a lawyer. She then successfully completed her second state examination and was admitted to the bar. She is a member of the German Bar Association and the Cologne Bar Association. Ms. Bond is a native German and English speaker and advises our clients competently in both languages.

Birte Windheuser

Ms. Windheuser completed her legal clerkship at the Regional Court of Aachen. During her legal clerkship, she already worked in our law firm and was able to make a significant contribution to our clients. Her university studies focused on international and European law. Ms. Windheuser can draw on a wealth of experience due to her longstanding voluntary work in the field of refugee aid. She has been involved in a welcome initiative since 2015, where she advises and supports refugees. She has also worked at a psychosocial center for refugees in Bochum in the past. Ms. Windheuser is also a great asset to our team due to her high level of intercultural competence. In addition to her native German, she is also fluent in English and Spanish. Through her international work assignments in Chile, Colombia and Bolivia and her first degree in “Regional Studies Latin America”, she was able to deepen her knowledge in this area.

Ms. Windheuser is a member of the German Bar Association and the Cologne Bar Association.

Leonie Kämpfer

Ms. Kämpfer studied law in Freiburg im Breisgau. During her studies, she advised people seeking legal advice as part of her voluntary work for a student legal advice association, where she was also active as a board member. During her legal clerkship at the Higher Regional Court of Hamm, she worked in a department for European law in the Bundestag in Berlin and thus deepened her expertise in cross-border cases. Since completing her second state examination and being admitted to the bar in 2021, Ms. Kämpfer has worked as a lawyer in a law firm specializing in migration law in the Cologne area. She has been part of our team at Maibaum Rechtsanwalts GmbH since June 2024.

Theresa Hollerith

Ms. Hollerith studied law in Bonn and Lyon. During her studies, she was already very committed to helping refugees and was involved in the Refugee Law Clinic Cologne. During her legal clerkship at the Higher Regional Court of Cologne, she worked at the German Embassy in Nairobi, among other places, where she gained important experience for her professional career. Since completing her second state examination and being admitted to the bar in April 2022, Ms. Hollerith has worked as a lawyer in a law firm specializing in migration law in the Cologne area. She has been part of our team at Maibaum Rechtsanwalts GmbH since May 2024. Ms. Hollerith advises our clients in English and French. Ms. Hollerith is a member of the Republican Lawyers’ Association (RAV).

Ozan Atas

Mr. Ozan Atas is a lawyer and specialist lawyer for migration law and social law. He studied law at the University of Bielefeld, specializing in asylum and social law. He completed his legal clerkship in 2016 in the district of the Hamm Higher Regional Court and worked as a trainee lawyer at the Bielefeld Public Prosecutor’s Office and the Bielefeld Regional Court. He then worked at the Federal Office for Migration and Refugees (BAMF) in the area of asylum and Dublin proceedings. Mr. Atas has been admitted to the bar since 2018 and worked in a medium-sized law firm in the Mönchengladbach area in the areas of migration, social and employment law. Mr. Atas has been part of our team at Maibaum Rechtsanwalts GmbH since June 2024. Mr. Atas is a member of the migration and social law working groups of the German Bar Association, a member of the Cologne Bar Association, a member of the Forum Junge Anwaltschaft and a board member of the Mönchengladbach Bar Association. Since 2023, he has been a volunteer supervisor for the Refugee Law Clinic (RLC) Düsseldorf. Mr. Atas advises our clients in English and Turkish.

Charlotte Waning

Ms. Waning studied law in Osnabrück and Budapest. During her semester abroad at Andrássy University in Budapest, she deepened her expertise in European law. Already during her legal clerkship, she volunteered for refugees and helped them prepare for their B1 German exam, among other things. After working as a lawyer in commercial law, Ms Waning specialized in migration law. Before joining the Maibaum Rechtsanwalts GmbH team in January 2025, Ms. Waning already worked as a lawyer in migration law, in particular in the field of nationality law. She advises our clients in German and English.

Ms. Waning is a member of the German Bar Association and the Cologne Bar Association.

Pauline Griestop

Pauline Griestop studied law at the Leibniz University of Hanover, where she passed her First State Examination.

During her studies, she was already committed to migration law issues at the Refugee Law Clinic Hannover and, among other things, took over as chairman of the board of the association from 2021 to 2022.

As part of her legal clerkship in the Higher Regional Court district of Cologne, she worked for a law firm in Cologne specializing in migration law and gained valuable experience in legal advice and the handling of immigration law proceedings.

Ms. Griestop joined our team in December 2025.

Ms. Griestop is a member of the Republican Bar Association (RAV).

Kiara Roddewig

Ms. Roddewig studied law at Johannes Gutenberg University in Mainz and passed her first state examination in law there. She then completed her specialization in criminology at the University of Bonn.

Even during her studies, Ms. Roddewig was involved with the Refugee Law Clinic in Mainz.

Since January 2024, she worked as a research assistant at a law firm specializing in immigration law in Cologne. Since May 2025, she has been fully committed to supporting the team at Maibaum Rechtsanwalts GmbH as a research assistant, assisting with client work and legal research.

Sandra Spillmann

Ms. Spillmann successfully completed her training as a paralegal in 1997. From 1999 to mid-2022, she worked in a law firm specializing in migration law. Since September, Ms. Spillmann has been a great asset to our clients as part of our service team due to her more than 20 years of professional experience.

Pia Adler

Pia Adler successfully completed her training as a paralegal in 2017. From 2018-2022, she worked at the law firm Gunter Christ in the field of immigration law. Since January 1, 2023, Ms. Adler has been a great asset to our clients thanks to her relevant professional experience in the field of immigration law.

Blerta Jonuzaj

Ms. Jonuzaj successfully completed her training as a paralegal in 2020 and already gained experience in migration law in her training firm. Ms. Jonuzaj has been part of our team since 2021 and works in the secretariat with great dedication for our clients. Ms. Jonuzaj is fluent in Albanian, Greek, German and English.

Lilian Tabatabai

Ms. Lilian Tabatabai is a trainee paralegal and is being trained at Maibaum Rechtsanwalts GmbH. Ms. Tabatabai works reliably and carefully and has a talent for organization. She can also express herself fluently in Persian and well in English. She is there for all our clients’ concerns.

Mohammed Alartouzi

Mr. Mohammed Alartouzi studied law in Beirut. In 2024, he successfully completed his training as a paralegal and already gained experience in migration law in his training firm. Since November 2024, Mr. Alartouzi has been part of the team in the secretariat of Maibaum Rechtsanwalts GmbH. He speaks Arabic and German.

Margit Krotz

Margit Krotz has many years of in-depth professional experience in finance and accounting. As Finance Assistant, she is responsible for managing key financial processes. Her extensive practical experience, highly structured approach, and high degree of accuracy and reliability ensure transparent, proper, and efficient financial operations.

Ostap Khomenko

Mr. Ostap Khomenko studied management in Ukraine and acquired additional qualifications in business law at the Cologne University of Applied Sciences. Prior to joining Maibaum Rechtsanwalts GmbH, he worked for over five years at a consumer law firm. Mr. Khomenko has been part of the Maibaum Rechtsanwalts GmbH team since June 2025 and, since December 2025, has served as Head of Office, responsible for the entire back office. Mr. Khomenko speaks Ukrainian, German, and Russian.