The French car maker awarded the contract, worth fees of at least £100,000, to Performance last week, following a five-way pitch that included Wyndham-Leigh.
The agency, which takes over the account in May, will promote Citroen's C1 city car and the C6 executive model, launching in June and at the end of the year respectively.
Citroen wants to use national, motorsports and lifestyle press, and events such as the Max Power Live shows - in Birmingham in July and London in December - to promote the new C1 (plus existing C2, C3 and C4 models) to young, urban men and women.
The strategy for the C6 is more closely guarded, but will focus on a more affluent market using aspirational and style magazines, as well as the motoring press.
Citroen UK comms director Marc Raven said: 'It is getting more competitive.
More manufacturers are offering different models. Now we are communicating greater choice.'
Citroen UK's market share of fleet and retail vehicle sales was 4.8 per cent for January to February, unchanged on the same period a year before.
But its share of retail sales alone increased to 6.7 per cent from 5.8 per cent in the previous year.