Twentysix is expected to complete the project by the end of summer.
Gail Dudleston, managing director of twentysix, said: "La Redoute is a great brand to work with and will help strengthen our expertise in the fashion and e-commerce sectors."
is owned by home shopping organisation Redcats.
Becki Smith, e-commerce manager at La Redoute, said: "We are extremely impressed with twentysix. Not only does the agency understand the dynamics of web design and online brand engagement, it is also expert in e-commerce and truly understands how to maximise revenues and ROI."
Earlier this week the agency announced it was launching an in-house search marketing division, headed by Ryan Scott.