The first planning phase involved a task-oriented inventory, the aim of which was to obtain a targeted assessment and analysis of the current situation in Mainz city center as a starting point for planning. In addition to compiling the available planning documents, existing expert reports, and concepts of the city of Mainz, this phase also involved gathering, evaluating, and documenting the different perspectives, expectations, and objectives for the development of Mainz city center. This was done in the context of two events.

First, on December 11, 2013, an initial workshop was held as a participation platform for Mainz experts, representatives of local associations, institutions, and clubs, as well as local politicians, with around 35 people taking part. In addition to providing information about the task at hand and the process design, the primary objectives were to intensify knowledge transfer among the participants and to discuss relevant topics relating to city center development.

Another component of this initial planning phase was the holding of an initial forum on March 6, 2014, at which citizens and other interested parties could obtain information about the process. In addition to an initial report on the status and background of the development, the aim was also to gather initial opinions from Mainz citizens on the strengths and weaknesses of Mainz city center and to obtain concrete ideas on specific locations and topics.

Parallel to the first forum, an online participation process was carried out between February 20 and March 27, 2014. This was intended to provide an additional opportunity to directly inform the planning team about the strengths, weaknesses, and wishes for the development of Mainz city center. The result of this first phase of the process was the development of a position paper, which served as a basis for further work by identifying the challenges and potential of the development. The content includes the identification of key challenges and opportunities for the future development of Mainz city center and a summary of the opinions gathered.

The second planning phase was devoted to developing key objectives and areas of action for inner city development as a basis for drafting the overall plan. First, a key issues paper was drawn up based on the previously developed position statement and the suggestions that had been recorded. The planning content, recommendations, and spatial fields of action in this paper were to be intensively discussed and debated with representatives of the professional public on July 27, 2014, as part of the second workshop. Following this workshop, the results were evaluated by the planning team and a first draft of the overall concept was then developed. The aim of this overall perspective was to highlight more clearly which thematic and spatial areas are of particular relevance for the future development of Mainz city center.

The aim of the third planning phase was to take a closer look at strategically important development priorities that play a key role in the attractiveness and functionality of Mainz city center. Against this backdrop, a location conference on the topic of "Große Langgasse" and a conference on the topic of city center as a residential location were held, at which the respective requirements for development were discussed in detail.

At the location conference on Große Langgasse on November 4, 2014, a small group of participants consisting of landowners, business owners, and other key users, as well as relevant stakeholders from politics and city administration and municipal associations, discussed the opportunities and potential for the development and redesign of Große Langgasse.

The primary goal of the "Housing" conference, which took place on February 3, 2015, was to bring together representatives of the Mainz city administration and local politicians with local and external experts from the housing industry to discuss potential opportunities and courses of action and to explore their feasibility. One of the main topics of discussion was how the residential function in Mainz city center can be further developed in a qualitative and socially acceptable manner.

The fourth planning phase served to consolidate the results into a spatial structural concept and to identify specific projects and measures.

Against this backdrop, a third workshop was held on March 19, 2015. The aim of this event was to present the draft of the overall plan and the list of projects and measures to the expert public and to discuss them together. The findings from this event served as the basis for the expert prioritization of the measures, which were supplemented following the workshop and then incorporated into the final phase of the overall concept and implementation.

In the fifth phase, the concept was implemented in a realization and implementation strategy. This illustrated the temporal and spatial dependencies between the individual measures and bundled them into project packages. In addition, it was necessary to identify sponsors for the individual measures, examine the time frames for subsequent implementation, and formulate priorities in the development process.

At a final forum held on May 19, 2015, the citizens of Mainz were able to obtain comprehensive information about the integrated development concept and once again identify their own priorities. These suggestions were incorporated into the further elaboration of the concept and evaluated by experts. Finally, the concept was formulated in the form of a report.