You can make a reasonable assessment of whether your match could be on your maternal side by consulting the Shared cM Project tool (link here). If you plug in 475 for the number of cM you match, you'll see that the possible relationships falls into one of three different level groups. The relationships within a group have equivalent amounts of relatedness. Close examination will show that the least-related group is the one with 8.1% likelihood, which is the one including 1C2R, first cousin twice removed. (The other groups have comparable relationships of 1C1R and 1C, which are closer relationships.) You'll want to consider the relationships in this least-related group because these will have the lowest possible cM values for your relationship, which will be the same relationship that your sister shares and thus shows whether an undetectable DNA match for her is possible.
To see the possible cM value ranges for each of the possible relationships in the 8.1% group, you'll probably want to open a second window using the same link but this time avoid filling in a cM value in the input box. This will avoid graying out many of the relationship boxes in the chart lower down on the page.
For each relationship in the group, find the corresponding entry in the chart and examine the third line of entry, which gives the cM range for that relationship. Note the lowest number of that range. After doing this for all the relationships in the group, you'll know the lowest cM value experienced for someone with the same relationship you have with your match (someone like your sister if the match is on your maternal side). My quick look at the table finds low cMs of 12, 43, 46, and 57. So the lowest cM seen by the project is 12 cM, and not zero. I believe you can take this to mean your match is almost certainly paternal, since based on this your sister would be expected to show a match of some size if you were related maternally to the match.