R.I.325 S.Jaffard M.Tucsnak Regularity of plate equations with control concentrated in interior curves The whole paper is available as a compressed Postscript file by internet procedure FTP anonymous on host barbes.polytechnique.fr ( 129.104.4.100) in the directory pub/RI/1995 under the name jaffard.tucsnak_325.jun.ps.gz or by Xmosaic or any other www client via the CMAP www server "http://blanche.polytechnique.fr/"