In the following reaction
3Br2 + 6CO32- + 3H2O → 5Br - + BrO3- + 6HCO3-
Bromine is reduced as well as oxidized
In the oxidation process the oxidation number of bromine changes from 0 (in Br2) to +5 (in BrO3-) and in reduction, oxidation number of bromine changes from 0 (in Br2) to -1 (in Br -).