Opposite the station information point in the central tunnel. 

Under the glass roof, north side centre (Meet & Go facade, in corner of the piano). 

On platform 1, south side, door no.3. 

On platform 3, south side (behind  the stairs of south underground...

There are 3 dispensers available at Strasbourg station: 

North concourse, central concourse and in front of entrance to the 2Theloo toilets in south underground passage.