The temperature of VFTS 259 (O6 Iaf) is based on the absence of the N iv λ4058 line. The line wings of the observations are narrower and He i λ4471 is too strong, which suggests a lower log g ≈ 3.5. Nitrogen is enriched, but N iii λ4634/4640 can only be reproduced by increasing the abundance additionally by a factor of two. C iii λ4647/4650 are present in the spectrum. Test models show that a reduction of log g, enhancing N, and moving the starting point of clumping closer to the surface, improves the fit quality, but only slightly change the derived parameters.