The company has appointed Brunswick in Tulchan's place at the behest of its new chairman and former Marks & Spencer CEO Luc Vandevelde.
Vandevelde, who became chairman of Carrefour at the start of this month, had a close relationship with Brunswick co-founder Alan Parker during his tenure at M&S.
Tulchan founder Andrew Grant was philosophical about the loss. 'We won the business on merit and lost it because of a relationship. These things happen,' he said.
Tulchan's dramatic displacement is a reversal of the firm's own ousting of Brunswick as M&S's retained financial comms adviser last year (PRWeek, 4 June 2004).
It followed M&S CEO Stuart Rose replacing Roger Holmes as M&S chief executive and Paul Myners replacing Vandevelde as chairman, in the midst of Phillip Green's attempt to buy the company.
Carrefour comms director David Shriver told PRWeek last month that Tulchan was briefed to increase Carrefour's profile with analysts and the financial media in New York and London.
Second only to Wal-Mart in international retail, Carrefour does not operate in the UK and US, and has a low profile with these countries' investment communities.
No-one at Brunswick or Carrefour was available for comment.