There is no relationship between the Organization of the conference and these hotels.
Here is a list of hotels that are relatively close to the venue:
Hotel Silken Ramblas
C/ Pintor Fortuny, 13, Barcelona
T. 933 42 61 80
https://www.hoteles-silken.com/es/hotel-ramblas-barcelona
Hotel Turin Barcelona
C/ Pintor Fortuny, 9, Barcelona
T. 933 02 48 12
https://hotelturinbarcelona.com/
Hotel Barceló Raval
C/ Rambla del Raval, 17, 21, Ciutat Vella
08001 Barcelona
https://www.barcelo.com/es-es/barcelo-raval
Hotel Catalonia Barcelona Plaza
C/ Bergara, 11, L’Eixample
08002 Barcelona
https://www.cataloniahotels.com/es/hotel/catalonia-barcelona-plaza
Residència d’Investigadors CSIC
C/Hospital, 64, Barcelona
934 43 86 10
https://resa.es/residencias/barcelona/