Fitch Ratings has affirmed UK's sovereign debt rating at 'AA+' on Friday. The outlook is stable.

"The UK's ratings benefit from a high-income, diversified and flexible economy. The credible monetary and fiscal policy framework and sterling's international reserve currency status further support the ratings," Fitch said in its statement.

The agency expects the French economy to expand 2.5% in 2015, 2.3% in 2016 and 2.1% in 2017.

"The mild growth slowdown has continued since the last rating review in June 2015," the agency noted.