Angelica Consiglio, president of Planin said the agency's experience with international accounts had secured it the account, with over 80% of its portfolio comprised of international clients.
Planin will provide media relations services, look after Alcatel's relationships with specialist media, and edit the company's publication to customers.
Consiglio will head the five-strong team in charge of the account, reporting to Alcatel's marketing and communications director Harumi Ishihara.
Planin's major challenge, Consiglio said, will be changing the perception that the public and the market have of Alcatel. The company wants to been seen as a solution provider, rather than an equipment maker.
Sao Paulo-headquartered Alcatel entered the Brazilian market in 1989 by buying local Elebra Telecom and Sesa. It has a factory in Sao Paulo.
Planin has 25 employees in its Sao Paulo office and works in partnership with 24 PR agencies Brazilwide.