A crystalline form of a salt of 3-[(dimethylamino)methyl]- N -{2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-1-benzofuran-2-carboxamide of formula: wherein HA is benzenesulfonic acid, oxalic acid, naphthalene-2-sulfonic acid, or naphthalene-1,5-disulfonic acid, or a hydrate thereof; and wherein: when HA is benzenesulfonic acid, the crystalline form of the salt of 3-[(dimethylamino)methyl]- N -{2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-1-benzofuran-2-carboxamide with benzenesulfonic acid has a powder X-ray diffraction diagram exhibiting the following diffraction lines (Bragg angle 2 theta, expressed in degrees ± 0.2°): 8.08; 10.03; 10.36; 13.63; 15.00; 16.19; 17.73; 17.90; 18.77; 19.77; 21.98; 22.45, when obtained with a copper anode with a K-alpha-1 wavelength of 1.54060 Å; when HA is oxalic acid, the crystalline form of the salt of 3-[(dimethylamino)methyl]-7V-{2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-1-benzofuran-2-carboxamide with oxalic acid has a powder X-ray diffraction diagram exhibiting the following diffraction lines (Bragg angle 2 theta, expressed in degrees ± 0.2°): 9.11; 9.67; 16.39; 17.73; 18.49; 18.65; 18.79; 21.96; 22.39; 23.39; 26.76; 27.92; 30.72, when obtained with a copper anode with a K-alpha-1 wavelength of 1.54060 Å; when HA is naphthalene-2-sulfonic acid, the crystalline form of the salt of 3-[(dimethylamino)methyl]- N -{2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-1-benzofuran-2-carboxamide with naphthalene-2-sulfonic acid has a powder X-ray diffraction diagram exhibiting the following diffraction lines (Bragg angle 2 theta, expressed in degrees ± 0.2°): 8.92; 9.33; 10.85; 17.89; 19.79; 21.79; 26.39, when obtained with a copper anode with a K-alpha-1 wavelength of 1.54060 Å; and when HA is naphthalene-1,5-disulfonic acid, the crystalline form of the salt of 3-[(dimethylamino)methyl]- N -{2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-1-benzofuran-2-carboxamide with naphthalene-1,5-disulfonic acid has a powder X-ray diffraction diagram exhibiting the following diffraction lines (Bragg angle 2 theta, expressed in degrees ± 0.2°): 6.87; 10.71; 11.31; 13.97; 18.51; 21.49; 21.84; 24.56, when obtained with a copper anode with a K-alpha-1 wavelength of 1.54060 Å. when HA is benzenesulfonic acid, the crystalline form of the salt of 3-[(dimethylamino)methyl]- N -{2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-1-benzofuran-2-carboxamide with benzenesulfonic acid has a powder X-ray diffraction diagram exhibiting the following diffraction lines (Bragg angle 2 theta, expressed in degrees ± 0.2°): 8.08; 10.03; 10.36; 13.63; 15.00; 16.19; 17.73; 17.90; 18.77; 19.77; 21.98; 22.45, when obtained with a copper anode with a K-alpha-1 wavelength of 1.54060 Å; when HA is oxalic acid, the crystalline form of the salt of 3-[(dimethylamino)methyl]-7V-{2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-1-benzofuran-2-carboxamide with oxalic acid has a powder X-ray diffraction diagram exhibiting the following diffraction lines (Bragg angle 2 theta, expressed in degrees ± 0.2°): 9.11; 9.67; 16.39; 17.73; 18.49; 18.65; 18.79; 21.96; 22.39; 23.39; 26.76; 27.92; 30.72, when obtained with a copper anode with a K-alpha-1 wavelength of 1.54060 Å; when HA is naphthalene-2-sulfonic acid, the crystalline form of the salt of 3-[(dimethylamino)methyl]- N -{2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-1-benzofuran-2-carboxamide with naphthalene-2-sulfonic acid has a powder X-ray diffraction diagram exhibiting the following diffraction lines (Bragg angle 2 theta, expressed in degrees ± 0.2°): 8.92; 9.33; 10.85; 17.89; 19.79; 21.79; 26.39, when obtained with a copper anode with a K-alpha-1 wavelength of 1.54060 Å; and when HA is naphthalene-1,5-disulfonic acid, the crystalline form of the salt of 3-[(dimethylamino)methyl]- N -{2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-1-benzofuran-2-carboxamide with naphthalene-1,5-disulfonic acid has a powder X-ray diffraction diagram exhibiting the following diffraction lines (Bragg angle 2 theta, expressed in degrees ± 0.2°): 6.87; 10.71; 11.31; 13.97; 18.51; 21.49; 21.84; 24.56, when obtained with a copper anode with a K-alpha-1 wavelength of 1.54060 Å.