Assistance system for assisting individuals (P1 - P3) temporarily present in a building, the assistance system comprising: a position determining system, for locating mobile devices (MG1 - MG5) situated in the building; first mobile devices (MG1 - MG3), which are each uniquely associated with an individual (P1 - P3) in the building, wherein the first mobile devices (MG1 - MG3) are set up to determine, in cooperation with the position determining system, the current position of one of the first mobile devices (MG1 - MG3), wherein the first mobile devices (MG1 - MG3) are further set up to send their current position to a server; second mobile devices (MG4, MG5), which are each uniquely associated with a service technician (SM1, SM2) in the building or for the building, wherein the second mobile devices (MG4, MG5) are set up to determine, in cooperation with the position determining system, the current position of one of the second mobile devices (MG4, MG5), wherein the second mobile devices (MG4, MG5) are further set up to send their current position to the server; a server, which is set up to communicate for data processing with the position determining system, the first mobile devices (MG1 - MG3) and the second mobile devices (MG4, MG5); wherein the server is further set up to generate, on request from one of the first mobile devices (MG1 - MG3) for assistance for the respective individual (P1 - P3) associated with this first mobile device (MG1 - MG3), an importance ranking in relation to the request; wherein the server is further set up, on the basis of the importance ranking of the request, the position of the respective first mobile device (MG1 - MG3) sending the request, and the position of a respective second mobile device (MG4, MG5), to send a message to the respective second mobile device (MG4, MG5) for user-side output, wherein the message comprises the position of the respective first mobile device (MG1 - MG3), characterised in that the message comprises personalised guidance for assisting the individual (P1 - P3) associated with the respective first mobile device, wherein the respective personalised guidance can be derived, for a respective individual (P1 - P3), from historical data and/or from social media data input by the individual. a position determining system, for locating mobile devices (MG1 - MG5) situated in the building; first mobile devices (MG1 - MG3), which are each uniquely associated with an individual (P1 - P3) in the building, wherein the first mobile devices (MG1 - MG3) are set up to determine, in cooperation with the position determining system, the current position of one of the first mobile devices (MG1 - MG3), wherein the first mobile devices (MG1 - MG3) are further set up to send their current position to a server; second mobile devices (MG4, MG5), which are each uniquely associated with a service technician (SM1, SM2) in the building or for the building, wherein the second mobile devices (MG4, MG5) are set up to determine, in cooperation with the position determining system, the current position of one of the second mobile devices (MG4, MG5), wherein the second mobile devices (MG4, MG5) are further set up to send their current position to the server; a server, which is set up to communicate for data processing with the position determining system, the first mobile devices (MG1 - MG3) and the second mobile devices (MG4, MG5); wherein the server is further set up to generate, on request from one of the first mobile devices (MG1 - MG3) for assistance for the respective individual (P1 - P3) associated with this first mobile device (MG1 - MG3), an importance ranking in relation to the request; wherein the server is further set up, on the basis of the importance ranking of the request, the position of the respective first mobile device (MG1 - MG3) sending the request, and the position of a respective second mobile device (MG4, MG5), to send a message to the respective second mobile device (MG4, MG5) for user-side output, wherein the message comprises the position of the respective first mobile device (MG1 - MG3), which is set up to communicate for data processing with the position determining system, the first mobile devices (MG1 - MG3) and the second mobile devices (MG4, MG5); wherein the server is further set up to generate, on request from one of the first mobile devices (MG1 - MG3) for assistance for the respective individual (P1 - P3) associated with this first mobile device (MG1 - MG3), an importance ranking in relation to the request; wherein the server is further set up, on the basis of the importance ranking of the request, the position of the respective first mobile device (MG1 - MG3) sending the request, and the position of a respective second mobile device (MG4, MG5), to send a message to the respective second mobile device (MG4, MG5) for user-side output, wherein the message comprises the position of the respective first mobile device (MG1 - MG3),