Acquisition of Grey Puts Focus on Havas  LONDON (Reuters) - WPP's &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=WPP.L target=/stocks/quickinfo/fullquote"&gt;WPP.L&lt;/A&gt; \$1.31 billion acquisition  of U.S.-based Grey Global takes it to the top of the  advertising sector and puts the spotlight on France's Havas  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=EURC.PA target=/stocks/quickinfo/fullquote"&gt;EURC.PA&lt;/A&gt;, which failed in its bid and may now become a  takeover target itself.