Validation attribute in XSD

I have a problem in a XSD,I need to validate an XML in XSD, but I have trouble to declare the attribute.

The attribute is:

<xs:attribute name='currency' type='xs:string'/>

Code in XML:

<price currency="€">30,65</price>

Code XSD:

<xs:element type="xs:string" name="information"/>
<xs:element type="xs:string" name="data"/>
<xs:element type="complexPrice" name="price"/>
<xs:complexType name="complexPrice">
  <xs:attribute name='currency' type='xs:string'/>
</xs:complexType>

This is error:

S4s-elt-must-match.1: The Content Of 'price' Must Match (annotation?, (simpleType | ComplexType)?, (unique | Key | Keyref))). A Problem Was Found Starting At: Attribute.*

Thanks for the help.