diff --git a/homeassistant/components/homematicip_cloud/sensor.py b/homeassistant/components/homematicip_cloud/sensor.py
index 1ed483b86ad..588e67bac95 100644
--- a/homeassistant/components/homematicip_cloud/sensor.py
+++ b/homeassistant/components/homematicip_cloud/sensor.py
@@ -46,6 +46,7 @@ from homeassistant.components.sensor import (
     SensorStateClass,
 )
 from homeassistant.const import (
+    CONCENTRATION_GRAMS_PER_CUBIC_METER,
     CONCENTRATION_MILLIGRAMS_PER_CUBIC_METER,
     DEGREE,
     LIGHT_LUX,
@@ -542,7 +543,9 @@ class HomematicipTemperatureSensor(HomematicipGenericEntity, SensorEntity):
 class HomematicipAbsoluteHumiditySensor(HomematicipGenericEntity, SensorEntity):
     """Representation of the HomematicIP absolute humidity sensor."""
 
-    _attr_native_unit_of_measurement = CONCENTRATION_MILLIGRAMS_PER_CUBIC_METER
+    _attr_device_class = SensorDeviceClass.ABSOLUTE_HUMIDITY
+    _attr_native_unit_of_measurement = CONCENTRATION_GRAMS_PER_CUBIC_METER
+    _attr_suggested_unit_of_measurement = CONCENTRATION_MILLIGRAMS_PER_CUBIC_METER
     _attr_state_class = SensorStateClass.MEASUREMENT
 
     def __init__(self, hap: HomematicipHAP, device) -> None:
@@ -550,7 +553,7 @@ class HomematicipAbsoluteHumiditySensor(HomematicipGenericEntity, SensorEntity):
         super().__init__(hap, device, post="Absolute Humidity")
 
     @property
-    def native_value(self) -> int | None:
+    def native_value(self) -> float | None:
         """Return the state."""
         if self.functional_channel is None:
             return None
@@ -564,8 +567,7 @@ class HomematicipAbsoluteHumiditySensor(HomematicipGenericEntity, SensorEntity):
         ):
             return None
 
-        # Convert from g/m³ to mg/m³
-        return int(float(value) * 1000)
+        return round(value, 3)
 
 
 class HomematicipIlluminanceSensor(HomematicipGenericEntity, SensorEntity):
diff --git a/tests/components/homematicip_cloud/test_sensor.py b/tests/components/homematicip_cloud/test_sensor.py
index 77e90ccaff6..669cbbf664f 100644
--- a/tests/components/homematicip_cloud/test_sensor.py
+++ b/tests/components/homematicip_cloud/test_sensor.py
@@ -776,7 +776,7 @@ async def test_hmip_absolute_humidity_sensor(
         hass, mock_hap, entity_id, entity_name, device_model
     )
 
-    assert ha_state.state == "6098"
+    assert ha_state.state == "6099.0"
 
 
 async def test_hmip_absolute_humidity_sensor_invalid_value(