* Due to publish new strategy plan on Jan. 23
* Lowers 2017 operating profit forecast again
* Q4 sales 23.328 bln euros, slightly above forecasts (Adds details and background)
PARIS, Jan 17 (Reuters) - Carrefour on Wednesday lowered its 2017 operating profit forecast for the second time in six months amid slowing full year sales, as its new boss prepares to unveil a revival plan for the world's second-largest retailer next week.
The French supermarket retailer, which ranks as No. 2 in its sector in the world behind Wal-Mart, said it now expected 2017 recurring operating profit at around 2 billion euros ($2.45 billion).
That would mark a year-on-year fall of 15 percent at current exchange rates, worse than the 12 percent drop Carrefour had forecast in August.
Several analysts had already been expecting Carrefour to tone down its 2017 profit estimates, given challenges it faces.
Carrefour, which is Europe's largest retailer, said 2017 sales reached 88.24 billion euros, a like-for-like rise of 1.6 percent but a slowdown from 3 percent growth achieved in 2016.
Fourth quarter sales alone, however, reached 23.328 billion euros, slightly above analysts' estimates of 23.2 billion euros.
Stripping out fuel, currency and calendar effects, fourth quarter revenue grew 1.9 percent year-on-year, a sequential improvement from 0.5 percent growth in the third quarter.
Improving the French hypermarket business is a priority for new boss Alexandre Bompard, who joined in July.
That goal has eluded several predecessors amid competition from online rivals and price discounting from other peers such as unlisted supermarket operator Leclerc.
Bompard will unveil his strategy for Carrefour on Jan. 23.
In France, where Carrefour makes 47 percent of its sales, like-for-like revenues rose 1.5 percent in a competitive environment following a 0.9 percent drop in the third quarter.
The improvement reflected a successful 'Black Friday' promotion campaign and year-end promotions, the company said.
French hypermarket sales also improved, advancing 0.7 percent in the fourth quarter after falling 1.7 percent in the third quarter.
However, deflation impacted Carrefour's sales growth in Brazil, its second-largest market after France.
Earlier on Wednesday, Carrefour's smaller rival Casino posted weaker fourth quarter sales, hitting its shares, with analysts disappointed by Casino's guidance for 2017 profit growth in its core French business.
($1 = 0.8175 euros) (Reporting by Dominique Vidalon; Editing by Sudip Kar-Gupta)