Paris-based Mazars, the fifth largest accountancy firm throughout most of Europe, has charged WS' financial services team with building its UK profile and positioning it as one of the country's top accountants outside the 'Big Four'.
The company has 18 offices and employs more than 1,100 in the UK, but it has not traditionally enjoyed the media presence of some of its second-tier accountancy rivals.
WS won the brief via a competitive pitch held in recent weeks, a process thought to have included four other agencies with a financial services pedigree.
Christian Ball, head of comms at Mazars, confirmed the appointment, commenting: 'We have some significant initiatives lined up to raise awareness of the market-leading services Mazars provides and needed an agency that could provide us with the same high level of service, satisfaction and care that we offer our clients.'
Weber Shandwick will look to help Mazars reach financial services audiences by increasing its voice in the specialist press and giving it a stronger presence in the national media.
Industry publication Accountancy Age this year listed Mazars as the twelfth largest accountancy firm in the UK and one of the few towards the top of the list to have grown its annual fee income.
Mazars audits more FT Global 500 companies than any non-big four firm and acts for more than 65 businesses in the UK.
Since its launch, Mazars has operated as an integrated partnership firm, which gives each partner the right to vote on the strategic decisions involving the future of the partnership.