Polar codes have been adopted as the coding scheme in the control channel of the 3rd Generation Partnership Project (3GPP) New Radio (NR) standard for 5G. However, the challenging requirements introduced by the 5G control channel in terms of block length and code rate flexibility render unsuitable most of the published hardware polar decoder implementations. Indeed, these latter focused mainly on successive cancellation decoders with ultra-high throughput, limited flexibility and error correction capabilities. With stringent constraints on end-toend delay and error correction, the 5G NR context steers towards lowlatency list-based decoder architectures. In this context, we propose an original flexible list-based hardware architecture for decoding 5G NR polar codes that can support all the frame sizes and code rates defined in 3GPP with a worst-case decoding latency below 24 µs.